Difunctional photoinitiators

ABSTRACT

The invention relates to α-hydroxy ketones of formula I or IIa; or mixtures of compounds of formula I and II; or mixtures of compounds of formulae Ia and IIa

The invention relates to initiators and mixtures thereof forcompositions that cure by means of radiation, especially usingultraviolet and visible radiation, to intermediates for theirpreparation, and to a process for the preparation of the initiators fromthe intermediates.

Systems that cure by means of radiation can be used in a large number ofapplications, for example in overprint coatings, printing inks, in themanufacture of electronic printed circuit boards and printing plates,and in the coating of various substrates, such as wood, plastics, paper,glass or metal. For the efficient polymerisation of such systems, it isnecessary to use a photoinitiator, from which, as a result ofinteraction with electromagnetic radiation, reactive particles such asfree radicals or cations (protons) are generated. A disadvantage of mostof the initiators frequently used in practice is the undesirable odourthat is produced when they are used. There is therefore a demand in theart for low-odour, low-volatility photoinitiators. In addition, it isdesirable for the photoinitiator to contribute towards an improvedcrosslinking density and to produce fewer photolysis products capable ofmigration. Moreover, the photoinitiator should be available in a formwhich is easy to handle, should cause minimal yellowing of the curedfilm, and should be readily soluble in systems that cure by means ofradiation.

A further important criterion for the use of photoinitiators is theeffectiveness with which the reactive constituents of the formulationare polymerised. This has a direct effect on the curing rate which canbe achieved during use, and on the degree of crosslinking of theresulting polymer.

European Patent Application EP-A 003 002 describes the use of particularketones as photoinitiators. The ketones have a tertiary alpha carbonatom which is substituted by a hydroxyl group or an amino group or anetherification or silylation product thereof. The compound4,4′-bis(α-hydroxy-isobutyryl)-diphenylmethane is listed by way ofexample, but its preparation is not described and characteristicproperties of the compound are not mentioned. European PatentApplication EP-A 003 002 also makes no reference to α-hydroxy ketonesthat contain water of crystallisation.

The most frequently used α-hydroxy ketone is Darocur 1173®(2-hydroxy-2-methyl-1-phenylpropan-1-one), a liquid photoinitiator whichis available commercially (from Ciba Specialty Chemicals).

It has now been found that α-hydroxy ketones of the following formulaepossess the required properties as photoinitiators.

The invention accordingly relates to novel crystalline and liquidα-hydroxy ketones of formula I or IIa

or mixtures of compounds of formulae I and II

or mixtures of compounds of formulae Ia and IIa

The compounds and mixtures having the formulae II and IIa arecrystalline and may be characterised by X-ray powder spectra accordingto FIGS. 1 to 5.

FIGS. 1 and 2 show the X-ray powder spectra of water-containing isomericmixtures of the compounds of formulae Ia and IIa.

FIG. 3 shows the X-ray powder spectrum of the water-free isomericmixture of the compounds of formulae I and II.

FIG. 4 shows the X-ray powder spectrum of the water-containing purepara-para compound of formula IIa.

FIG. 5 shows the X-ray powder spectrum of the water-free pure para-paracompound of formula II.

For the preparation of solvent-containing crystals there are suitablepolar solvents, for example water, aliphatic alcohols, for examplemethanol, ethanol; amines, for example tertiary amines. The solvent ispreferably water. The content of solvent (water) is from 2 to 8% byweight, preferably from 4 to 6% by weight.

In the preparation process there form first of all solvent-containing(water-containing) crystalline isomeric mixtures of the compounds offormulae Ia and IIa, from which solvent-free isomeric mixtures areformed by drying using drying agents.

The isomeric mixtures may contain the meta-para compound and thepara-para compound in any ratio by weight. However, preference is givento an isomeric mixture having a content of para-para compound of from99.9 to 25% by weight and having a content of meta-para compound of from0.1 to 75% by weight. Special preference is given to an isomeric mixturehaving a content of para-para compound of from 99.9 to 70% by weight andhaving a content of meta-para compound of from 0.1 to 30% by weight.

The preparation of the isomeric mixture is carried out according to thefollowing scheme:

-   a) Friedel-Crafts acylation

-   b) chlorination to bis(α-chloroisobutyryl)diphenylmethane,-   c) hydrolysis to bis(α-hydroxyisobutyryl)diphenylmethane,-   d) further processing to the solvent-containing crystalline isomeric    mixture,-   e) where appropriate, drying to form the solvent-free crystalline    isomeric mixture.

The preparation of the ketone is carried out by Friedel-Craftsacylation, wherein diphenylmethane is reacted with isobutyric acidhalide in the presence of a Lewis acid. The known Friedel-Craftscatalysts are suitable, for example aluminium chloride, aluminiumbromide, zinc chloride, tin chloride, iron(III) chloride, bismuthchloride or boron trifluoride. Aluminium chloride is preferred.

In the present Friedel-Crafts reaction, it Is possible first to bringthe aromatic compound and the catalyst together and to add the acidhalide thereto, as described in DE-OS 30 08 411 A1 (1980) of Merck.

It is, however, also possible first to bring the aromatic compound andthe acid halide together and to add the catalyst.

It has been found that the sequence of addition of the reagents iscritical to the success of the reaction. The best yields are obtainedwhen the aromatic compound and the acid halide are first broughttogether and the catalyst, preferably aluminium chloride, is slowlyadded thereto.

Suitable solvents are any solvents that are inert under the indicatedreaction conditions, for example ethylene chloride, trichloroethylene,methylene chloride, tetrachloroethane, chlorobenzene, bromobenzene,dichlorobenzene, cyclohexane, methylcyclohexane, carbon disulfide,nitromethane, nitroethane, nitropropane and nitrobenzene. Preference isgiven to chlorobenzene or ortho-dichlorobenzene.

The reaction temperature is from −20° C. to 20° C., preferably from 0°C. to 10° C., especially from 0° C. to 5° C.

For the reaction there is used an excess of acid halide, relative todiphenylmethane, of from 1.8 to 2.8 equivalents, preferably from 2.0 to2.6 equivalents, especially from 2.2 to 2.4 equivalents. Acid chlorideis preferred to acid bromide.

For the reaction there is used an excess of aluminium chloride, relativeto diphenylmethane, of from 1.9 to 2.9 equivalents, preferably from 2.0to 2.7 equivalents, especially from 2.3 to 2.5 equivalents. The excessof aluminium chloride should be at least as great as the excess of acidhalide.

In a further variant, the aluminium chloride may first be broughttogether with the solvent, and the acid halide may be added dropwise inexcess at from −20° C. to 10° C., with cooling. The aromatic compoundmay then slowly be added at from −20° C. to 10° C., with cooling.

The ketone of step (a) is obtained in the form of an isomeric mixtureand can be chlorinated directly in step (b) without being isolated.Chlorinating agents are sulfuryl chloride or chlorine gas. Thechlorination is preferably carried out by introduction of chlorine gasat a temperature from 20 to 70° C., preferably from 50 to 60° C. It isalso possible to carry out bromination with bromine.

Subsequent hydrolysis with aqueous alkali metal hydroxide (step c)yields the crude isomeric mixture consisting ofbis[4-(2-hydroxy-2-methyl-propionyl)-phenyl]-methane and[3-(2-hydroxy-2-methyl-propionyl)-phenyl]-[4-(2-hydroxy-2-methyl-propionyl)-phenyl]-methane,dissolved in the organic phase. It is advantageous to use a mixture ofmethanol and water for carrying out the hydrolysis.

At the core of the process according to the invention is the subsequentfurther processing of the crude isomeric mixture to form thesolvent-containing crystalline isomeric mixture of compounds of formulaeIa and IIa.

The warm organic phase is diluted, where appropriate, with a suitablesolvent, for example with toluene, and then a slightly polar solvent,preferably water (approximately 5 to 15% by weight of the amount of endproduct) is added thereto. The addition of polar solvent effectscrystallisation. Seeding may be carried out with water-containingcrystals, where appropriate. The crystals are filtered off, washed anddried. The drying temperature should not exceed 35 to 40° C., in orderto prevent sintering of the crystals. The resulting crystals are anisomeric mixture of para-para product and meta-para product in a goodyield and in a form which is easy to handle.

The crucial step in the process is the addition of polar solvent,preferably water, to the organic phase, as described above. Without theaddition of polar solvent, a rubber-like paste forms and no furthercrystals can be obtained from the mother liquor. A thick syrup isobtained, which may subsequently partly solidify.

A solvent-free isomeric mixture can be prepared by drying with a dryingagent. Examples of suitable drying agents are calcium chloride, calciumoxide, calcium sulfate, active aluminium oxide, magnesium sulfate,sodium sulfate, sodium carbonate, molecular sieves and furtherconventional drying agents. Sodium sulfate and calcium chloride arepreferred. To that end, the isomeric mixture is dissolved in a suitablesolvent, for example in toluene, and drying agent is added thereto.Evaporation of the solvent yields a viscous oil, which begins tocrystallise after some time.

The invention accordingly relates to a process for the preparation of acrystalline isomeric mixture of compounds of formulae Ia and IIa or Iand II, which comprises reacting diphenylmethane with isobutyric acidhalide in the presence of a Friedel-Crafts catalyst, and chlorinatingand hydrolysing the resulting isomeric mixture consisting ofbis[4-(2-methyl-propionyl)-phenyl]-methane and[3-(2-methyl-propionyl)-phenyl]-[4-(2-methyl-propionyl)-phenyl]methane,hydrolysis of the isomeric mixture yielding an aqueous phase and anorganic phase that comprises the hydrolysis product; wherein furtherprocessing of the hydrolysis product comprises the following steps

-   a) addition of from 3 to 20% by weight of polar solvent (water) to    the organic phase, crystallisation and isolation of the    solvent-containing Isomeric mixture (formulae Ia and IIa)-   b) where appropriate, drying of the isomeric mixture obtained in    step a) to obtain a solvent-free (water-free) crystalline isomeric    mixture.

In the isolation of the solvent-containing isomeric mixture (step a),the filtrate may, after removal of the crystalline para-para compound byfiltration, be subjected to steam distillation in order to remove thesolvent. An oil consisting mainly of the meta-para compound is obtained.That oil is likewise suitable as a photoinitiator.

The preparation of the pure para-para compound of formula II incrystalline form is carried out by fractional crystallisation. To thatend, for example, the isomeric mixture obtained after the Friedel-Craftsacylation in the first step is isolated by crystallisation. Purificationby crystallisation is also carried out in the second step ofchlorination (or bromination). As a result of the crystallisations, therelative proportions of the isomers are increasingly shifted in favourof the para-para compound, so that virtually pure para-para compound isobtained.

The preparation of the pure meta-para compound of formula I is carriedout at the ketone stage by crystallisation of the para-para compound. Asa result, the meta-para compound[3-(2-methyl-propionyl)-phenyl]-[4-(2-methyl-propionyl)-phenyl]-methanebecomes concentrated in the mother liquor and can be obtained from themother liquor by separation by means of HPLC. The chlorination (orbromination), hydrolysis and further processing are carried out asdescribed above.

The novel compounds of formula I or IIa and the isomeric mixtures(formulae Ia and IIa or I and II) are suitable quite generally asphotoinitiators.

The invention accordingly relates also to a composition comprising

-   (A) at least one ethylenically unsaturated compound,-   (B) a photoinitiator of formula I, II or IIa or an isomeric mixture    of compounds of formulae Ia and IIa or I and II,-   (C) optionally a film-forming binder based on a thermoplastic or    thermocurable resin;-   (D) optionally, further additives,-   (E) optionally, further photoinitiators and coinitiators.

The compounds of formulae I, Ia, II and IIa and their isomeric mixturesare suitable, inter alia, as photoinitiators for ethylenicallyunsaturated compounds containing at least one amino-acrylate.

The invention accordingly relates also to a composition comprising

-   (A) an ethylenically unsaturated compound containing at least one    aminoacrylate,-   (B) a photoinitiator of formula I, II or IIa or an isomeric mixture    of compounds of formulae Ia and IIa or I and II,-   (C) optionally a film-forming binder based on a thermoplastic or    thermocurable resin;-   (D) optionally, further additives,-   (E) optionally, further photoinitiators and coinitiators.    Suitable Ethylenically Unsaturated Compounds (A)

The unsaturated compounds (A) may contain one or more olefinic doublebonds. They may be low molecular weight (monomeric) or higher molecularweight (oligomeric).

Examples of monomers having a double bond are alkyl and hydroxyalkylacrylates and methacrylates, e.g. methyl, ethyl, butyl, 2-ethylhexyl and2-hydroxyethyl acrylate, isobornyl acrylate, and methyl and ethylmethacrylate. Further examples are acrylonitrile, acrylamide,methacrylamide, N-substituted (meth)acrylamides, vinyl esters, such asvinyl acetate, vinyl ethers, such as isobutyl vinyl ether, styrene,alkyl- and halo-styrenes, N-vinylpyrrolidone, vinyl chloride andvinylidene chloride.

Examples of monomers having a plurality of double bonds are ethyleneglycol diacrylate, propylene glycol diacrylate, neopentyl glycoldiacrylate, hexamethylene glycol diacrylate and bisphenol A diacrylate,4,4′-bis(2-acryloyloxyethoxy)diphenylpropane, trimethylolpropanetriacrylate, pentaerythritol triacrylate and pentaerythritoltetraacrylate, vinyl acrylate, divinylbenzene, divinyl succinate,diallyl phthalate, triallyl phosphate, triallyl isocyanurate andtris(2-acryloylethyl)isocyanurate.

Examples of higher molecular weight (oligomeric) polyunsaturatedcompounds are acrylated epoxy resins, acrylated or vinyl-ether- orepoxy-group-containing polyesters, polyurethanes and polyethers.

Further examples of unsaturated oligomers are unsaturated polyesterresins, which are usually produced from maleic acid, phthalic acid andone or more diols and have molecular weights of about from 500 to 3000.In addition it is also possible to use vinyl ether monomers andoligomers, and also maleate-terminated oligomers having polyester,polyurethane, polyether, polyvinyl ether and epoxide main chains.Combinations of vinyl-ether-group-carrying oligomers and polymers, asdescribed in WO 90/01512, are especially suitable, but copolymers ofmonomers functionalised with vinyl ether and maleic acid also come intoconsideration.

Also suitable are compounds having one or morefree-radical-polymerisable double bonds. The free-radical-polymerisabledouble bonds in such compounds are preferably in the form of(meth)acryloyl groups. Here and in the following, (meth)acryloyl and(meth)acrylic mean acryloyl and/or methacryloyl, and acrylic and/ormethacrylic, respectively. At least two polymerisable double bonds inthe form of (meth)acryloyl groups are preferably contained in themolecule. The compounds in question may be, for example,(meth)acryloyl-functional oligomeric and/or polymeric compounds ofpoly(meth)acrylate. The number-average molar mass of that compound maybe, for example, from 300 to 10 000, preferably from 800 to 10 000, Thecompounds preferably containing free-radical-polymerisable double bondsin the form of (meth)acryloyl groups can be obtained by customarymethods, for example by reaction of poly(meth)acrylates with(meth)acrylic acid. These and further preparation methods are describedin the literature and known to the person skilled in the art.

Such unsaturated oligomers can also be termed prepolymers.

Functional Polymers:

It is also possible to use as component (A) unsaturated acrylates havingreactive functional groups. The reactive functional group may beselected, for example, from a hydroxy, thiol, isocyanate, epoxide,anhydride, carboxy, amino and blocked amino group. Examples ofunsaturated acrylates containing OH groups are hydroxyethyl acrylates,hydroxybutyl acrylates and also glycidyl acrylates.

Examples of suitable monomers which are normally used to form thebackbone (the base polymer) of such functionalised acrylate andmethacrylate polymers are, for example, acrylate, methyl acrylate,methyl methacrylate, ethyl acrylate, ethyl methacrylate, n-butylacrylate, n-butyl methacrylate, isobutyl acrylate, isobutylmethacrylate, 2-ethylhexyl acrylate, 2-ethylhexyl methacrylate, etc. Inaddition, suitable amounts of functional monomers are copolymerisedduring the polymerisation in order thus to obtain the functionalpolymers. Acid-functionalised acrylate or methacrylate polymers areobtained with the aid of acid-functional monomers such as acrylic acidand methacrylic acid. Hydroxy-functional acrylate or methacrylatepolymers are obtained from hydroxy-functional monomers, such as2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate,3,4-dihydroxybutyl methacrylate, or from acrylates which are derivedfrom glycerol derivatives. Epoxy-functionalised acrylate or methacrylatepolymers are obtained with the aid of epoxy-functional monomers such asglycidyl methacrylate, 2,3-epoxybutyl methacrylate, 3,4-epoxybutylmethacrylate, 2,3-epoxycyclohexyl methacrylate, 10,11-epoxyundecylmethacrylate, etc. Likewise, isocyanate-functionalised polymers, forexample, can be produced from isocyanate-functionalised monomers, forexample meta-isopropenyl-α,α-dimethylbenzyl isocyanate.Amino-functionalised polymers are, for example, polyacrylamides, andnitrile-group-containing polymers are, for example, polyacrylonitriles.

Esters

Especially suitable are, for example, esters of ethylenicallyunsaturated mono- or polyfunctional carboxylic acids and polyols orpolyepoxides, and polymers having ethylenically unsaturated groups inthe chain or in side groups, e.g. unsaturated polyesters, polyamides andpolyurethanes and copolymers thereof, alkyd resins, polybutadiene andbutadiene copolymers, polyisoprene and isoprene copolymers, polymers andcopolymers having (meth)acrylic groups in side chains, and also mixturesof one or more such polymers.

Examples of suitable mono- or poly-functional unsaturated carboxylicacids are acrylic acid, methacrylic acid, crotonic acid, itaconic acid,cinnamic acid, maleic acid, fumaric acid, itaconic acid, and unsaturatedfatty acids such as linolenic acid and oleic acid. Acrylic andmethacrylic acid are preferred.

It is also possible, however, to use saturated di- or poly-carboxylicacids in admixture with unsaturated carboxylic acids. Examples ofsuitable saturated di- or poly-carboxylic acids include, for example,tetrachlorophthalic acid, tetrabromophthalic acid, phthalic anhydride,adipic acid, tetrahydrophthalic acid, isophthalic acid, terepthalicacid, trimellitic acid, heptanedicarboxylic acid, sebacic acid,dodecanedicarboxylic acid, hexahydrophthalic acid, etc.

Suitable polyols are aromatic and, especially, aliphatic andcycloaliphatic polyols. Examples of aromatic polyols are hydroquinone,4,4′-dihydroxydiphenyl, 2,2-di(4-hydroxyphenyl)propane, and novolaks andresols. Examples of polyepoxides are those based on the said polyols,especially the aromatic polyols and epichlorohydrin. Also suitable aspolyols are polymers and copolymers that contain hydroxyl groups in thepolymer chain or in side groups, e.g. polyvinyl alcohol and copolymersthereof or polymethacrylic acid hydroxyalkyl esters or copolymersthereof. Further suitable polyols are oligoesters having hydroxylterminal groups.

Examples of aliphatic and cycloaliphatic polyols include alkylenediolshaving preferably from 2 to 12 carbon atoms, such as ethylene glycol,1,2- or 1,3-propanediol, 1,2-, 1,3- or 1,4-butanediol, pentanediol,hexanediol, octanediol, dodecanediol, diethylene glycol, triethyleneglycol, polyethylene glycols having molecular weights of preferably from200 to 1500, 1,3-cyclopentanediol, 1,2-, 1,3- or 1,4-cyclohexanediol,1,4-dihydroxymethylcyclohexane, glycerol, tris(β-hydroxyethyl)amine,trimethylolethane, trimethylolpropane, pentaerythritol,dipentaerythritol and sorbitol.

The polyols may be partially or fully esterified by one or by differentunsaturated carboxylic acid(s), it being possible for the free hydroxylgroups in partial esters to be modified, for example etherified, oresterified by other carboxylic acids.

Examples of Esters are:

trimethylolpropane triacrylate, trimethylolethane triacrylate,trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate,tetramethylene glycol dimethacrylate, triethylene glycol dimethacrylate,tetraethylene glycol diacrylate, pentaerythritol diacrylate,pentaerythritol triacrylate, pentaerythritol tetraacrylate,dipentaerythritol diacrylate, dipentaerythritol triacrylate,dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate,dipentaerythritol hexaacrylate, tripentaerythritol octaacrylate,pentaerythritol dimethacrylate, pentaerythritol trimethacrylate,dipentaerythritol dimethacrylate, dipentaerythritol tetramethacrylate,tripentaerythritol octamethacrylate, pentaerythritol diitaconate,dipentaerythritol trisitaconate, dipentaerythritol pentaitaconate,dipentaerythritol hexaitaconate, ethylene glycol diacrylate,1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanedioldiitaconate, sorbitol triacrylate, sorbitol tetraacrylate,pentaerythritol-modified triacrylate, sorbitol tetramethacrylate,sorbitol pentaacrylate, sorbitol hexaacrylate, oligoester acrylates andmethacrylates, glycerol di- and tri-acrylate, 1,4-cyclohexanediacrylate, bisacrylates and bismethacrylates of polyethylene glycolhaving a molecular weight of from 200 to 1500, and mixtures thereof.

The following esters are also suitable: dipropylene glycol diacrylate,tripropylene glycol diacrylate, 1,6-hexanediol diacrylate, glycerolethoxylate triacrylate, glycerol propoxylate triacrylate,trimethylolpropane ethoxylate triacrylate, trimethylolpropanepropoxylate triacrylate, pentaerythritol ethoxylate tetraacrylate,pentaerythritol propoxylate triacrylate, pentaerythritol propoxylatetetraacrylate, neopentyl glycol ethoxylate diacrylate, neopentyl glycolpropoxylate diacrylate.

Amides

Also suitable as component (A) are the amides of identical or differentunsaturated carboxylic acids and aromatic, cycloaliphatic and aliphaticpolyamines having preferably from 2 to 6, especially from 2 to 4, aminogroups. Examples of such polyamines are ethylenediamine, 1,2- or1,3-propylenediamine, 1,2-, 1,3- or 1,4-butylenediamine,1,5-pentylenediamine, 1,6-hexylenediamine, octylenediamine,dodecylenediamine, 1,4-diaminocyclohexane, isophoronediamine,phenylenediamine, bisphenylenediamine, di-β-aminoethyl ether,diethylenetriamine, triethylenetetramine and di(β-aminoethoxy)- anddi(β-aminopropoxy)-ethane. Further suitable polyamines are polymers andcopolymers which may have additional amino groups in the side chain andoligoamides having amino terminal groups. Examples of such unsaturatedamides are: methylene bisacrylamide, 1,6-hexamethylene bisacrylamide,diethylenetriamine trismethacrylamide, bis(methacrylamidopropoxy)ethane,β-methacrylamidoethyl methacrylate andN-[(β-hydroxyethoxy)ethyl]-acrylamide.

Suitable unsaturated polyesters and polyamides are derived, for example,from maleic acid and diols or diamines. The maleic acid may have beenpartially replaced by other dicarboxylic acids. They may be usedtogether with ethylenically unsaturated comonomers, e.g. styrene. Thepolyesters and polyamides may also be derived from dicarboxylic acidsand ethylenically unsaturated diols or diamines, especially from thosehaving longer chains of e.g. from 6 to 20 carbon atoms. Examples ofpolyurethanes are those composed of saturated diisocyanates andunsaturated diols or unsaturated diisocyanates and saturated diols.

Aminoacrylates as Especially Suitable Components (A)

Especially suitable components (A) are acrylates which have beenmodified by reaction with primary or secondary amines, as described, forexample, in U.S. Pat. No. 3,844,916 of Gaske, in EP 280 222 of Weiss etal., in U.S. Pat. No. 5,482,649 of Meixner et al. or in U.S. Pat. No.5,734,002 of Reich et al., Such amine-modified acrylates are also termedaminoacrylates. Aminoacrylates are obtainable, for example, under thename EBECRYL 80, EBECRYL 81, EBECRYL 83, EBECRYL 7100 from UCBChemicals, under the name Laromer PO 83F, Laromer PO 84F, Laromer PO 94Ffrom BASF, under the name PHOTOMER 4775 F, PHOTOMER 4967 F from Cognisor under the name CN501, CN503, CN550 from Cray Valley.

The photopolymerisable compounds (A) can be used alone or in any desiredmixtures.

Component (C)

Component (C) is, for example, generally a film-forming binder based ona thermoplastic or thermocurable resin, predominantly on a thermocurableresin. Examples thereof are alkyd, acrylic, polyester, phenol, melamine,epoxy and polyurethane resins and mixtures thereof. Examples thereof aredescribed, for example, in Ullmann's Encyclopedia of IndustrialChemistry, 5th Ed., Vol. A18, pp. 368–426, VCH, Weinheim 1991.

Component (C) may be a cold-curable or hot-curable binder, with theaddition of a curing catalyst possibly being advantageous. Suitablecatalysts that accelerate the full cure of the binder are described, forexample, in Ullmann's Encyclopedia of Industrial Chemistry, Vol. A18,page 469, VCH Verlagsgesellschaft, Weinheim 1991.

Examples of particular binders suitable as component (C) are:

-   1. surface-coating compositions based on cold- or hot-crosslinkable    alkyd, acrylate, polyester, epoxy or melamine resins or mixtures of    such resins, optionally with the addition of a curing catalyst;-   2. two-component polyurethane surface-coating compositions based on    hydroxyl-group-containing acrylate, polyester or polyether resins    and aliphatic or aromatic isocyanates, isocyanurates or    polyisocyanates;-   3. two-component polyurethane surface-coating compositions based on    thiol-group-containing acrylate, polyester or polyether resins and    aliphatic or aromatic isocyanates, isocyanurates or polyisocyanates;-   4. single-component polyurethane surface-coating compositions based    on blocked isocyanates, isocyanurates or polyisocyanates, which are    unblocked during stoving; the addition of melamine resins is also    possible;-   5. single-component polyurethane surface-coating compositions based    on aliphatic or aromatic urethanes or polyurethanes and    hydroxyl-group-containing acrylate, polyester or polyether resins;-   6. single-component polyurethane surface-coating compositions based    on aliphatic or aromatic urethane acrylates or polyurethane    acrylates having free amine groups in the urethane structure, and    melamine resins or polyether resins, optionally with the addition of    a curing catalyst;-   7. two-component surface-coating compositions based on    (poly)ketimines and aliphatic or aromatic isocyanates, isocyanurates    or polyisocyanates;-   8. two-component surface-coating compositions based on    (poly)ketimines and an unsaturated acrylate resin or a    polyacetoacetate resin or a methacrylamidoglycolate methyl ester;-   9. two-component surface-coating compositions based on carboxyl- or    amino-group-containing polyacrylates and polyepoxides;-   10. two-component surface-coating compositions based on    anhydride-group-containing acrylate resins and a polyhydroxy or    polyamino component;-   11. two-component surface-coating compositions based on    acrylate-containing anhydrides, and polyepoxides;-   12. two-component surface-coating compositions based on    (poly)oxazolines and anhydride-group-containing acrylate resins, or    unsaturated acrylate resins or aliphatic or aromatic isocyanates,    isocyanurates or polyisocyanates;-   13. two-component surface-coating compositions based on unsaturated    (poly)acrylates and (poly)malonates;-   14. thermoplastic polyacrylate surface-coating compositions based on    thermoplastic acrylate resins or extrinsically crosslinking acrylate    resins, in combination with etherified melamine resins;-   15. surface-coating composition systems, especially clear    surface-coating compositions, based on malonate-blocked isocyanates    with melamine resins (e.g. hexamethoxymethylG16 melamine) as    crosslinker (acid-catalysed);-   16. UV-curable systems based on oligomeric urethane acrylates and/or    acylate acrylates, optionally with the addition of other oligomers    or monomers;-   17. dual-cure systems, which are first cured thermally and then    UV-cured, or vice versa, constituents of the surface-coating    composition containing double bonds which can be made to react by UV    light and photoinitiators and/or by electron-beam curing.    Further Additives (D)

In addition to the photoinitiator, the photopolymerisable mixtures mayoptionally comprise further conventional additives (D), depending on theintended use.

Examples thereof are:

-   antioxidants, optical brighteners, fillers, thermal inhibitors which    are intended to prevent premature polymerisation, for example    2,2,6,6-tetramethyl-4-hydroxy-piperidin-1-oxyl(4-hydroxy-TEMPO) and    derivatives thereof;-   antistatics, wetting agents or flow improvers and adhesion    enhancers;-   thermal drying or curing catalysts, for example organometallic    compounds, amines or/and phosphines;-   UV absorbers and light stabilisers, for example those from the group    of the 2-(2′-hydroxyphenyl)-benzotriazoles, of the    2-hydroxybenzophenones, esters of unsubstituted or substituted    benzoic acids, acrylates, sterically hindered amines, oxalic acid    diamides, 2-(2-hydroxy-phenyl)-1,3,5-triazines, phosphites and    phosphonites.

Examples of antioxidants, light stabilisers, UV absorbers or opticalbrighteners are:

-   ^(RTM)IRGANOX 1035, 1010, 1076, 1222, ^(RTM)TINUVIN P, 234, 320,    326, 327, 328, 329, 213, 292, 144, 622LD (commercially available    from Ciba Specialty Chemicals), ^(RTM)ANTIGENE P, 3C, FR, GA-80,    ^(RTM)SUMISORB TM-061 (commercially available from Sumitomo Chemical    Industries Co.), ^(RTM)SEESORB 102, 103, 501, 202, 712, 704    (commercially available from Sypro Chemical Co., Ltd.), ^(RTM)SANOL    LS770 (commercially available from Sankyo Co. Ltd.) ^(RTM)UVITEX OB,    commercially available from Ciba Specialty Chemicals.

Especially advantageous are additions of combinations of stericallyhindered piperidine derivatives (HALS) and sterically hindered phenols,for example additions of IRGANOX 1035 and TINUVIN 292, for example inthe ratio 1:1.

Photopolymerisation can also be accelerated by addition, as furtheradditives (D), of photosensitisers that shift or broaden the spectralsensitivity. These include especially aromatic carbonyl compounds, forexample benzophenone, thioxanthone, including especiallyisopropylthioxanthone, anthraquinone and 3-acylcoumarin derivatives,terphenyls, styryl ketones, and 3-(aroylmethylene)-thiazolines,camphorquinone and also eosin, rhodamine and erythrosine dyes.

The formulations may also comprise dyes and/or white or colouredpigments. Depending on the intended use, both inorganic and organicpigments may be used.

The additives (D) described above are conventional in the art andaccordingly are used in the amounts customary in the art.

It is also possible to add solvents or water to the compositions used inthe process according to the invention. Suitable solvents are solventswhich are known to the person skilled in the art and are conventionalespecially in coating technology. Radiation-curable aqueous prepolymerdispersions are obtainable commercially in many variations. They are tobe understood as being a dispersion of water and at least one prepolymerdispersed therein.

Further Photoinitiators (E)

It is, of course, also possible to use mixtures with knownphotoinitiators, for example mixtures with camphorquinone, benzophenone,benzophenone derivatives (e.g.1-[4-(4-benzoyl-phenylsulfanyl)-phenyl]-2-methyl-2-(toluene-4-sulfonyl)-propan-1-one),acetophenone, acetophenone derivatives, for example α-hydroxycycloalkylphenyl ketones or dialkoxyacetophenones, α-hydroxy- orα-amino-acetophenones, for exampleoligo-[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]-propanone],2-hydroxy-2-methyl-1-phenyl-propanone,2-hydroxy-1-[4-(2-hydroxy-ethoxy)-phenyl]-2-methyl-propan-1-one,2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-propan-1-one,2-dimethylamino-2-(4-methylbenzyl)-1-(4-morpholin-4-yl-phenyl)-butan-1-one,2-benzyl-2-dimethylamino-1-(3,4-dimethoxy-phenyl)-butan-1-one,2-benzyl-2-dimethylamino-1-(4-morpholin-4-yl-phenyl)-butan-1-one,2-methyl-1-(4-methylsulfanyl-phenyl)-2-morpholin-4-yl-propan-1-one,4-aroyl-1,3-dioxolanes, benzoin alkyl ethers and benzil ketals, forexample benzil dimethyl ketal, phenyl glyoxalates and derivativesthereof, for example methylbenzoyl formate, dimeric phenyl glyoxalates,for example oxo-phenyl-acetic acid2-[2-(2-oxo-2-phenyl-acetoxy)-ethoxy]-ethyl ester, peresters, forexample benzophenone-tetracarboxylic acid peresters, as described, forexample, in EP 126 541, monoacylphosphine oxides, for example(2,4,6-trimethylbenzoyl)-diphenyl-phosphine oxide orphenyl-(2,4,6-trimethylbenzoyl)-phosphinic acid ethyl ester,bisacylphosphine oxides, for examplebis(2,6-dimethoxybenzoyl)-(2,4,4-trimethyl-pent-1-yl)phosphine oxide,bis(2,4,6-trimethylbenzoyl)-phenyl-phosphine oxide orbis(2,4,6-trimethylbenzoyl)-(2,4-dipentoxyphenyl)phosphine oxide,trisacylphosphine oxides, halomethyltriazines, for example2-[2-(4-methoxy-phenyl)-vinyl]-4,6-bis-trichloromethyl-[1,3,5]triazine,2-(4-methoxy-phenyl)-4,6-bis-trichloromethyl-[1,3,5]triazine,2-(3,4-dimethoxy-phenyl)-4,6-bis-trichloromethyl-[1,3,5]triazine,2-methyl-4,6-bis-trichloromethyl-[1,3,5]triazine,hexaarylbisimidazole/coinitiator systems, for exampleortho-chlorohexaphenyl-bisimidazole together with2-mercaptobenzthiazole, ferrocenium compounds or titanocenes, forexample dicyclopentadienyl bis(2,6-difluoro-3-pyrrolo-phenyl)titanium,borate photoinitiators or O-acyloxime photoinitiators, as described, forexample, in GB 2 339 571.

It is also possible to add cationic photoinitiators, for example benzoylperoxide (other suitable peroxides are described in U.S. Pat. No.4,950,581, column 19, lines 17–25), or aromatic sulfonium, phosphoniumor iodonium salts, as described, for example, in U.S. Pat. No.4,950,581, column 18, line 60 to column 19, line 10.

An example of an iodonium salt is(4-isobutyl-phenyl)-4-methylphenyl-iodonium hexafluorophosphate.

Maleimide derivatives, as described, for example, in U.S. Pat. No.6,153,662 or U.S. Pat. No. 6,150,431 of First Chemicals, may also bepresent. Examples which may be mentioned areN-(2-trifluoromethylphenyl)maleimide andN-(2-tert-butylphenyl)maleimide.

The photopolymerisable compositions comprise the photoinitiatoradvantageously in an amount from 0.05 to 15% by weight, preferably from0.1 to 8% by weight, based on the composition. The indicated amount ofphotoinitiator relates to the sum of all added photoinitiators whenmixtures thereof are used, that is to say both to photoinitiator (B) andto photoinitiators (B)+(E).

Use

The photocurable compositions according to the invention are suitablefor various purposes, for example for overprint coatings, for printinginks, especially flexographic printing inks, for clear coats, whitecoats or colour-pigmented coats, e.g. for wood or metal; for powdercoatings, as coating materials for substrates of all kinds, e.g. wood,textiles, paper, ceramics, glass, glass fibres, plastics such aspolyester, polyethylene terephthalate, polyolefins or cellulose acetate,especially in the form of films, and also for metals such as Al, Cu, Ni,Fe, Zn, Mg or Co and GaAs, Si or SiO₂, to which there is to be applied aprotective layer or an image by image-wise exposure.

Examples of metal coatings are the coating of sheet metals and tubes,cans or bottle tops, as a finishing lacquer for applications in theautomotive industry.

Examples of the photocuring of paper coatings are the colourless coatingof labels or book covers.

The compounds according to the invention can also be used in the form ofan aqueous dispersion, for example from 0.5 to 5%, preferably from 0.5to 2%, in polymer dispersions, for example in water-containingpolyurethane dispersions, so-called PUD's.

The photopolymerisable compositions may also be used as daylight-curablepaints for marking structures and roads, for photographic reproductionprocesses, for holographic recording materials, for image-recordingprocesses or in the production of printing plates that can be developedusing organic solvents or using aqueous-alkaline media, for theproduction of masks for screen printing, as dental filling compounds, asadhesives, as pressure-sensitive adhesives, as laminating resins, asetch resists or permanent resists, both liquid and dry films, asphotostructurable dielectrics, and as solder masks for electroniccircuits, as resists in the production of colour filters for any type ofdisplay screen or in the creation of structures during the manufactureof plasma displays and electroluminescent displays, in the production ofoptical switches, optical gratings (interference gratings), in themanufacture of three-dimensional articles by bulk curing (UV curing intransparent moulds) or according to the stereolithography process, asdescribed, for example, in U.S. Pat. No. 4,575,330, in the manufactureof composite materials (e.g. styrene polyesters which may include glassfibres and/or other fibres and other adjuvants) of gel coats andthick-layered compositions, in the coating or sealing of electroniccomponents or as coatings for optical fibres. The compositions are alsosuitable for the production of optical lenses, e.g. contact lenses orFresnel lenses, and also in the manufacture of medical apparatus, aidsor implants. The compositions can also be used for the preparation ofgels having thermotropic properties. Such gels are described e.g. in DE197 00 064 and EP 678 534.

A preferred field of application is overprint coatings. These typicallyconsist of ethylenically unsaturated compounds such as oligomeric and/ormonomeric acrylates and amino-acrylates. Suitable compounds are listedunder “Compound (A)”. The compounds and mixtures according to theinvention are especially effective in overprint coatings of small layerthickness (from 5 to 10 μm).

A further preferred field of application is UV-curable flexographicprinting inks. These likewise consist of ethylenically unsaturatedcompounds (A) and also comprise UV flexo-resin binders as well asfurther additives, for example flow improvers and coloured pigments.

A further preferred field of application is powder coatings. The powdercoatings may be based on solid resins and monomers containing reactivedouble bonds (compounds (A)), for example maleates, vinyl ethers,acrylates, acrylamides and mixtures thereof. The powder coatings mayalso comprise binders, as are described, for example, in DE 4 228 514and EP 636 669. The UV-curable powder coatings may also comprise whiteor coloured pigments.

A further preferred field of application are powder coating compositionsapplied to substrates that are not heat-sensitive, for example to metals(automotive coatings), in said field of application it is also possibleto provide “dual cure” powder coating formulations using thephotoinitiators according to the invention. Such formulations are knownto the person skilled in the art and are both thermally cured andUV-cured. Such formulations can be found, for example, in U.S. Pat. No.5,922,473.

A further preferred field of application is dispersions.

Suitable dispersants are all surface-active compounds, preferablyanionic and non-ionic surfactants, as well as polymeric dispersants.Examples of dispersants which may be used according to the inventioninclude the following classes of compound:

1. Anionic Surfactants

-   1.1 lignosulfonates,-   1.2 dialkyl sulfosuccinates,-   1.3 sulfated or sulfonated fatty acids or fatty acid esters of fatty    acids,-   1.4 reaction products of ethylene oxide and/or propylene oxide with    saturated or unsaturated fatty acids, fatty alcohols, fatty amines,    alicyclic alcohols or aliphatic-aromatic hydrocarbons which have    been esterified in the terminal position by an inorganic    oxygen-containing acid or a polybasic carboxylic acid.

The anionic dispersants are normally in the form of their alkali metalsalts, their ammonium salts or their water-soluble amine salts.Low-electrolyte grades are advantageously used.

2. Non-ionic Surfactants

Ethylene oxide adducts from the class of the addition products ofethylene oxide with higher fatty acids, saturated or unsaturated fattyalcohols, fatty amines, mercaptans, fatty acid amides, fatty acidalkylol amides or fatty amines or with alkylphenols or withalkylthiophenols, with from 5 to 100 mol of ethylene oxide being usedper mol of the mentioned compounds, as well as ethylene oxide-propyleneoxide block polymers and ethylene-diamine-ethylene oxide-propylene oxideadducts.

These include: 2.1 reaction products of saturated and/or unsaturatedfatty alcohols having from 8 to 20 carbon atoms with from 20 to 100 molof ethylene oxide per mol of alcohol, preferably saturated linearC₁₆–C₁₈ alcohols with from 25 to 80 mol, especially 25 mol, of ethyleneoxide per mol of alcohol;

-   2.2 reaction products of saturated and/or unsaturated fatty acids    having from 8 to 20 carbon atoms with from 5 to 20 mol of ethylene    oxide per mol of acid;-   2.3 reaction products of alkylphenols having from 7 to 12 carbon    atoms with from 5 to 25 mol of ethylene oxide per mol of phenolic    hydroxy group, preferably mono- or dialkylphenols with from 10 to 20    mol of ethylene oxide per mol of phenolic hydroxyl group;-   2.4 reaction products of saturated and/or unsaturated fatty acid    amides having up to 20 carbon atoms with from 5 to 20 mol of    ethylene oxide per mol of acid amide, preferably oleic acid amides    with from 8 to 15 mol of ethylene oxide per mol of acid amide;-   2.5 reaction products of saturated and/or unsaturated fatty amines    having from 8 to 20 carbon atoms with from 5 to 20 mol of ethylene    oxide per mol of amine, preferably oleylamines with from 8 to 15 mol    of ethylene oxide per mol of amine;-   2.6 ethylene oxide-propylene oxide block polymers having from 10 to    80% ethylene oxide and molecular weights from 1000 to 80 000;-   2.7 ethylene oxide-propylene oxide adducts with ethylenediamine.    3. Polymeric Dispersants and Protective Colloids

Suitable polymeric dispersants are, for example, amphiphilic copolymers,block copolymers or graft or comb polymers, especially those based onacrylic acid, methacrylic acid or salts thereof,hydroxyalkyl(meth)acrylic acid, aminoalkyl(meth)acrylic acid or saltsthereof, 2-acrylamido-2-methylpropanesulfonic acid (AMPS) or saltsthereof, maleic anhydride or salts thereof, (meth)acrylamide orsubstituted (meth)acrylamides, vinyl heterocycles, for examplevinylpyrrolidone, vinylimidazole, as well as amphiphilic polymerscontaining segments of PEO or EO/PO copolymers.

Examples of suitable protective colloids are polyvinyl alcohol,polyvinylpyrrolidone or its copolymers.

Also suitable are copolymers of synthetic monomers, especially ofmonomers having carboxyl groups, for example copolymers of2-vinylpyrrolidone with 3-vinylpropionic acid or maleic acid copolymersand salts thereof.

Preferred dispersants are polymers based on maleic anhydride, polyvinylalcohol or modified polyacrylates, for example the alkali metal salts,especially the sodium salts, of carboxylic acid copolymers or polyvinylalcohol.

The substrates can be coated by applying a liquid composition, asolution or a suspension to the substrate. The choice of solvent and itsconcentration are governed chiefly by the nature of the composition andthe coating method. The solvent should be inert, that is to say itshould not enter into any chemical reaction with the components, and itshould be capable of being removed again on drying after the coatingoperation. Suitable solvents include, for example, ketones, ethers andesters, such as methyl ethyl ketone, isobutyl methyl ketone,cyclopentanone, cyclohexanone, N-methylpyrrolidone, dioxane,tetrahydrofuran, 2-methoxyethanol, 2-ethoxyethanol,1-methoxy-2-propanol, 1,2-dimethoxyethane, ethyl acetate, n-butylacetate and ethyl 3-ethoxypropionate.

The formulation is applied uniformly to a substrate by means of knowncoating methods, for example by spin-coating, immersion, knife coating,curtain pouring, brush application or spraying, especially byelectrostatic spraying and reverse-roll coating, and also byelectrophoretic deposition. It is also possible to apply thephotosensitive layer to a temporary flexible support and then coat thefinal substrate by transferring the layer via lamination. Examples oftypes of application are to be found, for example, in Ullmann'sEncyclopedia of Industrial Chemistry, 5th Edition, Vol. A18, pp.491–500.

The amount applied (layer thickness) and the nature of the substrate(layer support) are dependent on the desired field of application. Therange of dry layer thicknesses generally includes values from about 0.1μm to more than 100 μm.

The photosensitivity of the compositions according to the inventionusually extends from approximately 200 nm to within the IR range.Suitable radiation is present, for example, in sunlight or light fromartificial light sources. Accordingly a large number of the most variedkinds of light source may be used. Both point sources and planiformradiators (lamp carpets) are suitable. Examples are: carbon arc lamps,xenon arc lamps, medium-pressure, high-pressure and low-pressure mercuryradiators, doped, where appropriate, with metal halides (metal halidelamps), microwave-excited metal vapour lamps, excimer lamps,superactinic fluorescent tubes, fluorescent lamps, argon incandescentlamps, flash lamps, e.g. high-energy flash lamps, photographicfloodlight lamps, light-emitting diodes (LED), electron beams andX-rays. The distance between the lamp and the substrate to be exposedmay vary according to the intended use and the type and strength of thelamp and may be, for example, from 2 cm to 150 cm. Especially suitableare laser light sources, for example excimer lasers, such as Krypton-Flasers for exposure at 248 nm. Lasers in the visible range may also beused.

As already mentioned, curing in the process according to the inventioncan be carried out simply by irradiation with electromagnetic radiation.Depending on the composition of the formulation to be cured, however,thermal curing before, during or after the irradiation is advantageous.

Thermal curing is carried out by methods known to the person skilled inthe art. In general, the curing is carried out in an oven, e.g. acirculating air oven, on a hot plate or by irradiation with IR lamps.Unassisted curing at room tempeature is also possible, depending on thebinder system used. The curing temperatures are generally between roomtemperature and 150° C., for example from 25 to 150° C. or from 50 to150° C. In the case of powder coatings or coil coatings, the curingtemperatures may be even higher, e.g. up to 350° C.

The invention relates also to a process for the production of ascratch-resistant durable surface, wherein

a composition comprising at least one aminoacrylate and a photoinitiatorof formula I, II or IIa or an isomeric mixture of compounds of formulaeIa and IIa or I and II is applied to a support; and curing of theformulation is carried out either only by means of irradiation withelectromagnetic radiation having a wavelength of from 200 nm to withinthe IR range, or by irradiation with electromagnetic radiation andprior, simultaneous and/or subsequent action of heat.

The invention relates also to the use of the above-described compositionand to a process for the production of pigmented and non-pigmentedsurface coatings, overprint coatings, formulations for printing inks,powder coatings, dispersions, gel coats, composite materials or glassfibre cable coatings.

The invention relates also to a coated substrate which is coated on atleast one surface with a composition as described above.

The following Examples further illustrate the invention:

EXAMPLE 1 Preparation of a Crystalline Isomeric Mixture (Formulae Ia andIIa) Containing Water of Crystallisation

1.1) Friedel-Crafts Reaction

109.4 g (0.65 mol) of diphenylmethane, 159.3 g (1.495 mol) of isobutyricacid chloride and 150 ml of 1,2-dichlorobenzene are combined and cooledto 5–0° C. In the course of about four hours, 208.0 g (1.56 mol) ofaluminium chloride are added in small portions at an internaltemperature of 5–0° C. HCl gas is evolved. Stirring is then carried outfor about 16 hours at an internal temperature of 0–5° C. At the end ofthat period, all the aluminium chloride has dissolved. The dark-redreaction mixture is then poured onto ice and water and stirred tocomplete the reaction. The two phases are separated in a separatingfunnel. The organic phase is washed with water and then concentrated fora short time in a vacuum rotary evaporator at about 60° C. and about 25mbar. 403.1 g of a yellow liquid are obtained. The product, an isomericmixture with bis[4-(2-methyl-propionyl)-phenyl]-methane as the maincomponent, is used in the next reaction without being purified further.Excluding the solvent 1,2-dichlorobenzene, 87.3% p,p-isomer, 11.4%m,p-isomer, 0.66% m,m-isomer and 0.60% p-mono compound are found in theGC and ¹H-NMR spectrum.

1.2) Enol Chlorination

403.1 g (0.65 mol) solution of the isomeric mixture ofbis[4-(2-methyl-proplonyl)-phenyl]-methane with[3-(2-methyl-propionyl)-phenyl]-[4-(2-methyl-proplonyl)-phenyl]-methanefrom the Friedel-Crafts reaction are heated to 55–60° C. by means of anoil bath. 92.2 g (1.30 mol) of chlorine gas are then introduced througha glass frit at 55–60° C., with thorough stirring, more rapidly at thebeginning and only slowly at the end. HCl gas is evolved. The durationof the introduction is about 6 hours. 441.5 g of a yellowish liquid areobtained. The product, an isomeric mixture withbis[4-(2-chloro-2-methyl-propionyl)-phenyl]-methane as the maincomponent, is used in the next reaction without being purified further.Excluding the solvent 1,2-dichlorobenzene, about 87% p,p-isomer andabout 12% m,p-isomer are found in the ¹H-NMR spectrum.

1.3) Hydrolysis

Variant 1.3a

Rapid Crystallisation for Working-up of the Hydrolysis Product

208.0 g (1.56 mol) of NaOH concentrated to 30% and 208 ml of deionisedwater and 205.7 g of methanol are combined. There are then addeddropwise at 50° C. in a period of about one hour, with thoroughstirring, 441.5 g (0.65 mol) of a solution, in 1,2-dichlorobenzene, ofthe isomeric mixture ofbis[4-(2-chloro-2-methyl-propionyl)-phenyl]-methane with[3-(2-chloro-2-methyl-propionyl)-phenyl]-[4-(2-chloro-2-methyl-propionyl)-phenyl]-methanefrom the chlorination reaction, additionally diluted with 102.8 g ofmethanol. The internal temperature slowly rises to 55–60° C. Thealkaline mixture (about pH 12) is then stirred for about three to fourhours at 55–60° C. The conversion is checked with a GC sample and a¹H-NMR sample. The mixture is then cooled to 45° C. and adjusteddropwise to a pH of about 2–3 with about 63.5 g of 16% hydrochloricacid. The colour of the emulsion changes from a strong yellow to yellow.The mixture is then stirred for about 30 minutes. When the hydrolysis iscomplete, the reaction mixture is neutralised with a small amount ofdilute sodium hydroxide solution. The two phases are separated at about50° C. in a separating funnel. 200 ml of water are added to the organicphase, which is then stirred and separated off again. The organic phaseis the solution of an isomeric mixture withbis[4-(2-hydroxy-2-methyl-propionyl)-phenyl)-methane as the maincomponent. About 88% p,p-isomer and about 11% m,p-isomer are found inthe ¹H-NMR spectrum. The warm organic phase is diluted with solvent (400ml of toluene), and a small amount of water (about 23 g of water, about10% of the amount of end product) is added thereto. The solution isseeded at 40–35° C. with water-containing crystals and is later cooledafter the crystallisation. The thick suspension is filtered and washedwith toluene and hexane in order to displace the 1,2-dichlorobenzene.The crystals are dried in vacuo to constant weight. 177.7 g of whitecrystals containing water of crystallisation are obtained. Thiscorresponds to a yield of 76.3% of theory (358.44) over all threereaction steps. The crystals of the isomeric mixture melt at 68–70° C.and contain 5.02% by weight water. The crystals exhibit an X-ray powderspectrum with the characteristic lines at a 2-theta angle of 6.69; 9.67;13.95; 15.11; 16.35; 17.57; 19.43; 21.39; 22.17; 23.35; 25.93; 27.11;27.79; 28.73; 34.83; 41.15. (FIG. 1)

Elemental analysis: (358.44)

% C % H calculated: 70.37 calculated: 7.31 found: 70.35 found: 7.37Variant 1.3bSlow Crystallisation for Working-up of the Hydrolysis Product

The isomeric mixture obtained in Example 1.2 is hydrolysed analogouslyto Variant 1.3a. About 88% p,p-isomer(bis[4-(2-hydroxy-2-methyl-propionyl)-phenyl]-methane) and about 11%m,p-isomer are found in the GC and ¹H-NMR spectrum. After separating theorganic phase and the aqueous phase, the warm organic phase (about 55°C.) is diluted with 250 ml of toluene, and about 30 g of water are thenadded thereto. The solution begins to crystallise spontaneously at 36°C., and the temperature rises to 42° C. The suspension, which hasthickened, is diluted with 75 ml of toluene and stirred for one hourwithout cooling. The experiment is left to stand overnight and on thefollowing morning is cooled to 5° C. using an ice-water bath. The cold,thick suspension is filtered and washed with 75 ml of toluene and 140 gof hexane mixture In order to displace the 1,2-dichlorobenzene. Themoist filtration product is weighed, 204.5 g of moist white crystals,and halved. A portion of the crystals is immediately dried, a portion ofthe crystals is subjected to after-treatment. The mother liquor and thesolvent used for washing are together concentrated in vacuo. 45.5 g ofbrown liquid residue are obtained. About 42% p,p-isomer and about 58%m,p-isomer, determined by evaluation of the integrals of the aromaticprotons, are found in the ¹H-NMR spectrum.

The 102.3 g of white crystals are dried in vacuo to constant weight.88.19 of white, flocculent, voluminous crystals containing water ofcrystallisation are obtained. This corresponds to a yield of 75.6% oftheory (358.44) over all three reaction steps. The crystals of theisomeric mixture melt at 71–74° C. and contain 5.12% by weight wateraccording to Karl Fischer water determination. FIG. 2 shows the X-raypowder spectrum with the characteristic lines at a 2-theta angle of6.69; 9.69; 14.03; 15.15; 16.41; 17.57; 19.47; 19.75; 21.39; 22.19;23.33; 25.91; 27.05; 27.79; 28.67; 41.05.

Elemental analysis: (358.44)

% C % H calculated: 70.37 calculated: 7.31 found: 70.24 found: 7.39Variant 1.3cAfter-treatment

The other half, 102.2 g of moist white crystals, is dissolved with 150 gof toluene and heated for distillation. 68 g of toluene and 15 g ofwater are distilled off, final temperature about 110° C. in thesolution. The solution is slowly cooled and left to stand overnight. Onthe following morning, all the material is still dissolved. The solutionis seeded with water-free crystals, with stirring. It slowlycrystallises out. The suspension Is later diluted with 60 g of toluene,then cooled to 5° C., filtered and washed with 90 g of toluene. Thewhite crystals are dried in vacuo to constant weight. 71.7 g of white,hard, compact crystals are obtained. This corresponds to a yield of64.8% of theory (340.42) over all three reaction steps. The crystals ofthe isomeric mixture melt at 87–90° C. and contain 2.02% by weight wateraccording to Karl Fischer water determination. The mother liquor and thesolvent used for washing are together concentrated in vacuo. 12.3 g ofyellowish oil are obtained.

Variant 1d

Change of Solvent Before the Hydrolysis

1 d.2) Enol Chlorination

Analogously to Example 1, the Friedel-Crafts reaction and the enolchlorination are carried out with 1,2-dichlorobenzene as solvent. 460.6g of a yellowish liquid are obtained. The product, an isomeric mixturewith bis[4-(2-chloro-2-methyl-propionyl)-phenyl]-methane as the maincomponent, is freed of the solvent 1,2-dichlorobenzene by means of steamdistillation before the next reaction. The head temperature in thedistillation is about 95° C. and the distillation lasts about 4 hours.About 145 ml of 1,2-dichlorobenzene are recovered. The residue, ayellowish emulsion, is diluted with 195 g of toluene and separated fromthe water while still warm. There are obtained 462.7 g of organic phase,which is used in the next reaction without being purified further.Excluding the new solvent toluene, about 87% p,p-isomer and about 12%m,p-isomer are found in the GC and ¹H-NMR spectrum.

1d.3) Hydrolysis

208.0 g (1.56 mol) of NaOH concentrated to 30% and 208 ml of deionisedwater and 205.7 g of methanol are combined. The temperature rises toabout 38° C. The mixture is then heated to 50° C. by means of an oilbath. There are then added dropwise in a period of about one hour, withthorough stirring, 462.7 g (0.65 mol) of a solution, in toluene, of theisomeric mixture of bis[4-(2-chloro-2-methyl-propionyl)-phenyl]-methanewith[3-(2-chloro-2-methyl-propionyl)-phenyl]-[4-(2-chloro-2-methyl-propionyl)-phenyl]-methanefrom the chlorination reaction, additionally diluted with 103 g ofmethanol. The internal temperature slowly rises to 55–60° C. Thealkaline mixture (about pH 11) is then stirred for about three to fourhours at 55–60° C. The conversion is checked with a ¹H-NMR sample. Themixture is then cooled to 27° C. and adjusted dropwise to a pH of about1–2 with about 73.4 g of 16% hydrochloric acid. The colour of theemulsion changes from red to reddish. The mixture is then stirred forabout 100 minutes at 55–60° C. When the hydrolysis is complete, thereaction mixture is neutralised with about 9.4 g of dilute sodiumhydroxide solution (15%). The two phases are separated at about 50° C.in a separating funnel. 200 ml of toluene and 200 ml of water are addedto the organic phase, which is then stirred and separated off again. Theorganic phase is an isomeric mixture withbis[4-(2-hydroxy-2-methyl-propionyl)-phenyl]-methane as the maincomponent. About 88% p,p-isomer and about 11% m,p-isomer are found inthe GC and ¹H-NMR spectrum. The warm organic phase is again diluted with300 ml of toluene, and then about 30 g of water are added thereto. Thesolution is seeded at 40–35° C. with water-containing crystals and islater heated to about 50° C. after the crystallisation. The thicksuspension is slowly cooled and later cooled further by means of anice-water bath. It is then filtered and washed with 200 ml of toluene.The white crystals are dried in vacuo to constant weight. 173.1 g ofwhite, voluminous crystals containing water of crystallisation areobtained. This corresponds to a t.q. yield of 74.3% of theory (358.44)over all three reaction steps. The crystals of the isomeric mixture meltat 70.6–71.7° C. and contain 4.8% by weight water according to KarlFischer water determination.

The mother liquor and the solvent used for washing are togetherconcentrated in vacuo. 47.7 g of residue, a reddish viscous oil, areobtained.

1d.4) Enol Chlorination

Analogously to Example 1.1 and 1.2, the Friedel-Crafts reaction and theenol chlorination are carried out using 1,2-dichlorobenzene as solvent.457.2 g of a yellowish liquid are obtained. The product, an isomericmixture with bis[4-(2-chloro-2-methyl-propionyl]phenyl]-methane as themain component, is freed of the solvent 1,2-dichlorobenzene before thenext reaction by means of steam distillation. The head temperature inthe distillation is about 95° C. and the distillation lasts about 4hours. About 150 ml of 1,2-dichlorobenzene are recovered. The residue, ayellowish emulsion, is diluted with 195 g of toluene and separated fromthe water while still warm. There are obtained 459.7 g of organic phase,which is used in the next reaction without being purified further.Excluding the new solvent toluene, about 87% p,p-isomer and about 12%m,p-isomer are found in the GC and ¹H-NMR.

1d.5) Hydrolysis

459.7 g (0.65 mol) of a solution, in toluene, of the isomeric mixture ofbis[4-(2-chloro-2-methyl-propionyl)-phenyl]-methane with[3-(2-chloro-2-methyl-propionyl)-phenyl]-[4-(2-chloro-2-methyl-propionyl)-phenyl]-methanefrom the chlorination reaction are introduced into a reaction flask anddiluted with 308.5 g of methanol. The mixture is then heated to 50° C.by means of an oil bath. 208.09 (1.56 mol) of NaOH concentrated to 30%are then added dropwise in a period of about one hour, with thoroughstirring. The internal temperature slowly rises to 55–60° C. Thealkaline mixture (about pH 11) is then stirred for about 3 hours at55–60° C. The conversion is checked with a ¹H-NMR sample. The mixture isthen cooled to 40° C. and adjusted dropwise to a pH of about 1–2 withabout 58.2 g of 16% hydrochloric acid. The colour of the emulsionchanges from red to reddish. The mixture is then stirred further forabout 2 hours at 55–60° C. When the hydrolysis is complete, the reactionmixture is neutralised with about 4.3 g of dilute sodium hydroxidesolution (15%). The two phases are separated at about 50° C. in aseparating funnel. 200 ml of toluene and 200 ml of water are added tothe organic phase, which is then stirred and separated off again. About88% p,p-isomer and about 11% m,p-isomer are found in the ¹H-NMRspectrum. The warm organic phase is diluted again with 300 ml oftoluene, and then about 30 g of water are added thereto. The solutionbegins to crystallise out at 38° C. and is later heated to about 50° C.again after the crystallisation. The suspension is slowly cooled andlater cooled further by means of an ice-water bath. It is then filteredand washed with 200 ml of toluene. The white crystals are dried in vacuoto constant weight. 180.5 g of white crystals containing water ofcrystallisation are obtained. This corresponds to a t.q. yield of 77.5%of theory (358.44) over all three reaction steps. The crystals of theisomeric mixture melt at 72.1–74.7° C. and contain 4.7% by weight wateraccording to Karl Fischer water determination. The overall content ofmeta-para compound in the crystals is determined indirectly at the endof Example 1 e.

1 d.5a) Purifcation of the Mother Liquor

The mother liquor and the solvent used for washing are togetherconcentrated in vacuo. 40.0 g of a reddish viscous oil are obtained. Theoil is purified by means of flash chromatography over silica gel 60(0.040–0.063 mm) from Merck. A mixture of ethyl acetate:hexane mixture1:2 is used as eluant. 28.5 g of yellow-reddish oil are isolated as themain fraction. It is a pure product in the thin-layer chromatogram.About 36% p,p-isomer and about 64% m,p-isomer, determined by evaluationof the Integrals of the aromatic protons, are found in the ¹H-NMRspectrum.

Variant 1 e

Determination of the Distribution of Isomers after Crystallisation

Analogously to Example 1, diphenylmethane is acylated with isobutyricacid chloride in 1,2-dichlorobenzene, the diketone mixture is thenchlorinated without intermediate purification, and hydrolysis is finallycarried out with sodium hydroxide solution and with the addition ofmethanol. The distribution of isomers between the para-para compound andthe meta-para compound, about 12% meta-para compound, is maintained overall three steps, because no product is separated off untilcrystallisation. After separation of the aqueous phase, toluene andwater are added analogously to Example 1.3b. The solution crystallisesout at about 30° C. It is heated again to about 50° C., until almost allthe material has dissolved, and the suspension is then stirred whilecold. On the following morning, the mixture is cooled to 5° C. by meansof an ice-water bath and then filtered after 5 hours. The crystals arewashed with toluene and hexane mixture in order to displace the1,2-dichlorobenzene. The 173.2 g of white crystals are dried in vacuo atabout 30° C. to constant weight. 148.4 g of fine-grained white crystalscontaining water of crystallisation are obtained. This corresponds to ayield of 78.6% of theory (358.44) over all three reaction steps (0.5265mol). The crystals of the isomeric mixture melt at 71–73° C. and contain4.6% by weight water according to Karl Fischer water determination.After several weeks, the melting range stabilises at 76.0–77.5° C.

The mother liquor, 528 g of yellowish solution, is concentrated in avacuum rotary evaporator and then freed of solvent 1,2-dichlorobenzeneby means of steam distillation. The head temperature in the distillationis about 95° C. and the distillation lasts about one hour. The oil isseparated from the water and then freed of solvent completely at about60° C. and under a good vacuum (0.5 mbar). 36.79 of thick brownish oilare obtained. About 42% p,p-isomer and about 58% m,p-isomer, determinedby evaluation of the integrals of the aromatic protons, are found in the¹H-NMR spectrum of the concentrated mother liquor.

The crystals have only a small amount of m,p-isomer in the ¹H-NMRspectrum. The proportion of meta-para compound in the crystals was for along time uncertain because of the resonances of the secondary productsand the traces of 1,2-dichlorobenzene, which occur at the same locationsin the ¹H-NMR spectrum. Without removal of 1,2-dichlorobenzene by priorsteam distillation, the integral for the meta-para isomer in the ¹H-NMRspectrum is not visible.

In order better to determine and monitor the distribution of isomersbetween the para-para compound and the meta-para compound in thecrystals, a larger sample is recrystallised from toluene and water. Theexact procedure is as follows:

A sample of 120.0 g of crystalline product from Example 1e is dissolvedin 180 g of toluene at 55° C., and 20 g of water are added thereto. Thesolution is then allowed to cool slowly, with stirring. It crystallisesat about 49° C., with a rise in temperature to about 56° C. It isstirred overnight, without cooling, to complete the reaction and is thencooled to about 5° C. After two hours, filtration through a suctionfilter is carried out. The filtration product is washed with 30 g ofcold toluene and dried in vacuo in a drying cabinet between roomtemperature and 40° C. There are obtained 118.3 g of hard whitecrystals, which melt at 74–79° C. The toluenic mother liquor (about 195g) is concentrated and dried. There remain 1.7 g of yellowish oil, whichshows about 60% meta-para compound in the ¹H-NMR spectrum (300 MHz).This corresponds to 1.0 g of meta-para compound, which corresponds to acontent of about 0.85% of meta-para compound in the crystals used. Afurther analogous recrystallisation of a sample of 100 g of the obtainedcrystals from toluene and water gives a toluenic filtrate which, afterconcentration to 4.6 g of colourless oil, shows about 2.0% of meta-paracompound in the ¹H-NMR spectrum. This corresponds to 0.1 g of meta-paracompound, which corresponds to a content of about 0.10% of meta-paracompound in the crystals used. The two contents of about 0.85% and about0.10% are added together, and the total content of meta-para compound inthe tested crystals is from about 0.9% to about 1.0%. This estimate isnow sufficiently accurate.

In an analogous manner, a sample of 120.0 g of crystalline product fromExample 1 d.5 is dissolved in 180 g of toluene at 62° C., and 23 g ofwater are added thereto. The solution is cooled and crystallised in thesame manner. The suspension is stirred overnight to complete thereaction, and is then filtered at room temperature. The crystals arewashed with 90 g of toluene and dried in vacuo in a drying cabinetbetween room temperature and 40° C. There are obtained 114.1 g of hardwhite crystals, which melt at 70–76° C. The toluenic mother liquor isconcentrated and dried. There remain 5.1 g of yellowish oil, which showsabout 36% meta-para compound in the ¹H-NMR spectrum (300 MHz). Thiscorresponds to 1.84 g of meta-para compound, which corresponds to acontent of about 1.5% meta-para compound, which was extracted from thecrystals used. The total content of meta-para compound in the testedcrystals is estimated at from about 1.5% to about 1.7%. The directestimation of the total content of meta-para compound from the ¹H-NMRspectrum (300 MHz) by evaluation of the integrals of the aromaticprotons is no longer reliable with such small amounts.

Variant 1f

Change of solvent after hydrolysis and adjustment of the ratio ofisomers in the crystals Analogously to Example 1, diphenylmethane isacylated with isobutyric acid chloride in 1,2-dichlorobenzene, then thediketone mixture is chlorinated without intermediate purification, andhydrolysis is finally carried out with sodium hydroxide solution andwith the addition of methanol. The distribution of isomers in thereaction mixture between the para-para compound and the meta-paracompound, about 12% meta-para compound, is maintained over all threesteps, because no product is separated off until crystallisation. Afterseparation of the aqueous phase, the organic phase, in a modification ofExample 1, is subjected to steam distillation at about 95–100° C., andthe 1,2-dichlorobenzene is removed. About 154 g of 1,2-dichlorobenzeneare recovered. There is obtained a thick yellow oil, which tends tocrystallise with water below 60° C. The oil is crystallised with a largeamount of water without further solvent. Slow cooling yields moist,light-yellow spherules, which are filtered off and dried in vacuo atabout 35–40° C. In the ¹H-NMR spectrum of the crystals, the distributionof isomers between the para-para compound and the meta-para compound isthe same as in the ¹H-NMR spectrum of a sample of the oil, i.e. about88% para-para isomer and about 12% meta-para isomer. It no longercontains any 1,2-dichlorobenzene to interfere with the evaluation of the¹H-NMR spectrum. The light-yellow crude product is also surprisinglypure in the TLC. There are obtained 222.9 g of yellowish granules, whichmelt at 63–72° C. This corresponds to a yield of 95.7% over threereaction steps with a starting batch size of 0.65 mol (Example 1f).

From that crude product, by means of controlled crystallisations fromwater with variously small additions of toluene, it is possible toproduce products having selected compositions of the isomers.Accordingly, a portion of the meta-para compound can be filtered offwith the variously small amounts of toluene. From the toluenic filtrateand its isomeric composition in the ¹H-NMR spectrum, as well as theamount of crystals and their isomeric composition in the ¹H-NMRspectrum, it is possible to calculate and confirm the isomericcomposition in the crystals more exactly.

A 60 g sample of that yellowish crude product is heated and melted in 90g of water. 90 g of toluene are added at about 80° C. The mixture iscooled slowly and crystallised, and the suspension is filtered andwashed with water. The crystals are dried in vacuo. There are obtained50 g of slightly yellowish crystals, which melt at 67–72° C. Evaluationof the ¹H-NMR spectrum in the oil from the concentrated filtrate, 7.0 gof yellowish oil, shows about 75% meta-para compound and about 25%para-para compound. On calculating back that loss to the 50 g ofcrystals, a new content of about 3.9% of meta-para compound in thecrystals is determined. This is confirmed by evaluation of the ¹H-NMRspectrum of the crystals, which contain about 4% meta-para compound(Example 1fa).

A further 60 g sample of the yellowish crude product is heated andmelted in 50 g of water. 40 g of toluene are added at about 80° C. Themixture is cooled slowly and crystallised, and the suspension isfiltered and washed with water. The crystals are dried in vacuo. Thereare obtained 54 g of yellowish crystals, which melt at 66–72° C.Evaluation of the ¹H-NMR spectrum in the oil from the concentratedfiltrate, 4.7 g of yellowish oil, shows about 75% meta-para compound andabout 25% para-para compound. On calculating back that loss to the 54 gof crystals, a new content of about 6.8% of meta-para compound in thecrystals is determined. This is confirmed by evaluation of the ¹H-NMRspectrum of the crystals, which contain about 7% meta-para compound(Example 1fb).

EXAMPLE 2 Preparation of a Water-Free Crystalline Isomeric Mixture fromthe Corresponding Water-Containing Isomeric Mixture

The crystalline starting material from Example 1.3a which is used meltsat 68–70° C. and contains 5.02% by weight water. The crystals show anX-ray powder spectrum with the characteristic lines at a 2-theta angleof 6.69; 9.67; 13.95; 15.11; 16.35; 17.57; 19.43; 21.39; 22.17; 23.35;25.93; 27.11; 27.79; 28.73; 34.83; 41.15. (FIG. 1)

30 g of the isomeric mixture from Example 1.3a are heated to 70° C. In170 g of toluene, in order to dissolve the product. At 65° C., all thematerial has dissolved. The few drops of water cannot be separated offin a separating funnel. 10 g of water-free calcium chloride are thenadded to the toluene solution. Stirring is carried out for one hour at65° C., followed by filtration. The toluene solution is concentrated invacuum rotary evaporator and dried under a high vacuum. 25.2 g ofyellowish oil are obtained, which begins to crystallise slowly aftermore than 24 hours. The crystals of the isomeric mixture melt at89.2–91.2° C. and contain 0.09% by weight water according to KarlFischer water determination. FIG. 3 shows the X-ray powder spectrum withthe characteristic lines at a 2-theta angle of 10.71; 11.19; 16.43;17.25; 17.87; 21.53; 22.59; 25.99; 28.75.

Elemental analysis of the end sample: (340.42)

% C % H calculated: 74.09 calculated: 7.11 found: 73.65 found: 7.04

EXAMPLE 3 Preparation ofbis[4-(2-hydroxy-2-methyl-propionyl)-phenyl]-methane, Compound ofFormula IIa or II

3.1) Friedel-Crafts Reaction and Separation

168.2 g (1.0 mol) of diphenylmethane, 245.1 g (2.3 mol) of isobutyricacid chloride and 150 ml of 1,2-dichlorobenzene are combined and cooledto 5–0° C. by means of an ice bath. The acylation is carried outanalogously to Example 1.

After working up, the organic phase is washed with water and thenconcentrated in a vacuum rotary evaporator at about 60° C. and about 25mbar. The organic phase is then concentrated completely under a highvacuum. There are obtained 395.8 g of a yellow liquid, which stillcontains some solvent 1,2-dichlorobenzene. This corresponds to a crudeyield of 128% of theory. The product is an isomeric mixture withbis[4-(2-methyl-propionyl)-phenyl]-methane as the main component, and86.7% p,p-isomer, 11.1% m,p-isomer, 0.7% m,m-isomer and 1.5% p-monocompound are found in the ¹H-NMR spectrum, excluding the solvent1,2-dichlorobenzene. The product is dissolved in 100 ml of hexane andcrystallised out in a refrigerator. The crystals are filtered off,washed with cold hexane and dried in vacuo. There are obtained 169 g ofwhite crystals, which are again dissolved in 70 ml of warm hexane. Theproduct crystallises again and is filtered off, washed and dried. Thereare obtained 160 g of white crystals, which melt at 42–44° C. 97.3%para-para isomer and 2.7% meta-para isomer are now found in the GC and¹H-NMR spectrum.

The filtrate, about 350 g, is set aside and processed separately inExample 4.1.

Elemental analysis: (308.42)

% C % H calculated: 81.78 calculated: 7.84 found: 81.84 found: 7.983.2) Enol Chlorination of p,p-Diketone,bis[4-(2-methyl-propionyl)-phenyl]-methane

60.0 g (0.1945 mol) of recrystallizedbis[4-(2-methyl-propionyl)-phenyl]-methane with 2.7%[3-(2-methyl-propionyl)-phenyl-[4-(2-methyl-propionyl)-phenyl]-methanefrom the Friedel-Crafts reaction are dissolved in 150 ml ofchlorobenzene and heated to 55–60° C. by means of an oil bath. Thechlorination is carried out analogously to Example 1.2. There areobtained 73.8 g of a yellowish liquid, which begins to crystallise. Theproduct is recrystallised from 75 g of hexane and then from 65 g ofmethanol, filtered and dried. There are obtained 30.6 g of whitecrystals, which melt at 70.4–73.1° C. 99% p,p-isomer and about 1%m,p-isomer are now found in the ¹H-NMR spectrum.

Elemental analysis: (377.31)

% C % H % Cl calculated: 66.85 calculated: 5.88 calculated: 18.79 found:66.94 found: 6.02 found: 19.203.3a) Hydrolysis of p,p-dichloro Compound,bis[4-(2-chloro-2-methyl-propionyl)-phenyl]-methane

25.0 g (0.066 mol) ofbis[4-(2-chloro-2-methyl-propionyl)-phenyl]-methane from thechlorination reaction, dissolved in 30 g of toluene and 10 g ofmethanol, are hydrolysed analogously to Example 1, Variant 1.3a. Afterseparation of the organic phase, the warm organic phase (about 50° C.)is diluted with solvent (30 ml of toluene), and about 3 g of water arethen added thereto. The solution begins to crystallise spontaneously atabout 30° C. After working up analogously to Example 1, Variant 1.3b,19.2 g of white, granular crystals containing water of crystallisationare obtained. This corresponds to a yield of 80.8% of theory (358.44) ofbis[4-(2-hydroxy-2-methyl-propionyl)-phenyl]-methane. >99% para-paraIsomer and <1% meta-para Isomer are then found in the ¹H-NMR spectrum.The crystals melt at 77.9–78.7° C. and contain 4.82% by weight wateraccording to Karl Fischer water determination.

3.3b) Water-Free, Isomer-Freebis[4-(2-hydroxy-2-methyl-propionyl)-phenyl]-methane

5 g of the crystals containing water of crystallisation (Example 3.3a)are dissolved in 50 ml of toluene and heated to 60° C. 5 g of anhydrouscalcium chloride are then added, and stirring is carried out for twohours. The suspension is filtered and the filtrate is concentrated in avacuum rotary evaporator to about 20 ml. The product begins tocrystallise at room temperature overnight. The crystals are washed witha small amount of toluene and dried in vacuo. 2.8 g of white crystalsare obtained. >99.5% para-para isomer and <0.5% meta-para isomer arethen found in the ¹H-NMR spectrum. The crystals melt at 91.3–92.0° C.and contain <0.1% by weight water according to Karl Fischer waterdetermination.

Elemental analysis: (340.42)

% C % H calculated: 74.09 calculated: 7.11 found: 73.71 found: 7.113.3c) Recrystallisation of the Isomer-free Hydrolysis Product

50 g of isomer-free bis[4-(2-hydroxy-2-methyl-propionyl)-phenyl]-methanecontaining water of crystallisation are heated to 70° C. in 75 g oftoluene in order to dissolve the product. At 68° C., all the materialhas dissolved. A further 7.8 g of water are added. The temperature iscontrolled by means of an oil bath. At 50° C., the first crystals beginto form spontaneously. When crystallisation is complete, the suspensionis filtered over a suction filter and washed with 62.5 g of coldtoluene. The 55.4 g of white crystals are dried in vacuo to constantweight. 44.7 g of white, granular, compact crystals containing water ofcrystallisation are obtained. The crystals of the isomer-free productmelt at 81.8–84.3° C. and contain 5.10% by weight water according toKarl Fischer water determination. FIG. 4 shows the X-ray powder spectrumwith the characteristic lines at a 2-theta angle of 6.67; 9.65; 14.00;14.85; 15.15; 15.47; 15.95; 16.41; 17.69; 19.81; 20.21; 21.39; 22.17;22.61; 23.39; 25.91; 27.13; 27.91; 28.67.

The mother liquor is concentrated in vacuo. There are obtained 1.1 g ofyellowish oil, which crystallises.

Elemental analysis of the end sample: (358.44)

% C % H calculated: 70.37 calculated: 7.31 found: 70.05 found: 7.29

EXAMPLE 4 Preparation of[3-(2-hydroxy-2-methyl-propionyl)-phenyl]-[4-(2-hydroxy-2-methyl-propionyl)-phenyl]-methane,Compound of Formula I

4.1) Friedel-Crafts Reaction and Separation

168.2 g (1.0 mol) of diphenylmethane, 245.1 g (2.3 mol) of isobutyricacid chloride and 150 ml of 1,2-dichlorobenzene are combined and cooledto 5–0° C. by means of an ice bath. The acylation is carried out inExample 3.1.

After working up, the organic phase is concentrated in Example 3.1 andcrystallised from hexane. The crystals,bis[4-(2-methyl-propionyl)-phenyl]-methane, are recrystallised fromhexane again and chlorinated in Example 3.2. The filtrate, about 350 g,is processed separately in Example 4.1.

The filtrate from Example 3.1 is concentrated in a vacuum rotaryevaporator and then combined with other suitable dichlorobenzenesolutions from the Friedel-Crafts reaction. 100 g of water are added tothe yellow solution, and the mixture is freed of the solvent,1,2-dichlorobenzene, by means of steam distillation. The headtemperature In the distillation is about 95° C. and the distillationlasts about 4 hours. About 155 ml of 1,2-dichlorobenzene are recovered.The residue is separated from the water. 170.4 g of yellowish oil areobtained. 58 g of hexane are added, and dissolution is carried out whilehot. The solution is cooled, to room temperature, and then cooledfurther by means of an ice-bath. White crystals are formed. They arefiltered off and washed with about 150 g of hexane. The mother liquor isconcentrated in a vacuum rotary evaporator. 80 g of yellow-reddish oilare obtained, which shows about 24% m,p-isomer in the ¹H-NMR spectrum. Afurther 20 g of hexane are added to the oil, and the mixture is placedin a refrigerator for the purposes of crystallisation. The liquid isdecanted off and concentrated in a vacuum rotary evaporator. 45 g ofyellow-reddish oil are obtained, which shows about 37% m,p-isomer in the¹H-NMR spectrum. The various crystalline portions are dried and used forthe preparation of pure p,p-isomer.

The liquid portion of 45 g is separated in portions over a preparativeHPLC column from Varian. Since the separation is incomplete, only thefirst fractions are collected at the top and the rear fractions are fedback again because they contain too much p,p-isomer. After many passesthrough the column, there are obtained from the front fractions 1.9 g ofmeta-para isomer,[3-(2-methyl-propionyl)-phenyl]-[4-(2-methyl-propionyl)-phenyl]-methane,which in the GC and ¹H-NMR, contains about 94% m,p-isomer and stillcontains about 3% m,m-isomer and about 3% p,p-isomer. The 1.9 g ofyellowish oil collected are brominated without being purified further.

4.2) Enol Bromination of m,p-Diketone,[3-(2-methyl-propionyl)-phenyl]-[4-(2-methyl-propionyl)-phenyl]-methane

1.96 g (6.16 mmol) of separated[3-(2-methyl-propionyl)-phenyl]-[4-(2-methyl-propionyl)-phenyl]-methaneare dissolved in 20 ml of chlorobenzene, and one drop of chlorosulfonicacid is added thereto. 1.97 g (12.32 mmol) of bromine are then dissolvedin 50 ml of chlorobenzene and added dropwise at room temperature in aperiod of about 3 hours. The conversion is checked with a ¹H-NMRspectrum. The slightly yellowish solution is concentrated in a rotaryevaporator. 2.9 g of yellow oil,[3-(2-bromo-2-methyl-propionyl)-phenyl]-[4-(2-bromo-2-methyl-propionyl)-phenyl]-methane,are obtained.

4.3) Hydrolysis of m,p-dibromo Compound,[3-(2-bromo-2-methyl-propionyl)-phenyl]-[4-(2-bromo-2-methyl-propionyl)-phenyl]-methane

2.0 g (15 mmol) of NaOH concentrated to 30%, 20 ml of deionised waterand 20 ml of methanol are combined and heated to 50° C. by means of anoil bath. 2.9 g (6.16 mmol) of[3-(2-bromo-2-methyl-propionyl)-phenyl]-[4-(2-bromo-2-methyl-propionyl)-phenyl]-methane,dissolved In 20 ml of toluene and 10 ml of methanol, are then addeddropwise, with thorough stirring, in a period of about one hour. Thealkaline mixture (about pH 12) is then stirred for about three hours at55–60° C. The conversion is checked with a ¹H-NMR sample. The mixture isthen adjusted dropwise to a pH of about 1–2 with about 1.0 g of 16%hydrochloric acid and stirred at 50° C. for one hour in order tocomplete the reaction. The conversion is checked with a ¹H-NMR sample.When the hydrolysis is complete, the reaction mixture is neutralisedwith a small amount of dilute sodium hydroxide solution. The two phasesare separated in a separating funnel. The organic phase is concentratedin a rotary evaporator. 2.8 g of brownish oil are obtained (Example4.3). It is dissolved in 20 ml of toluene and washed with 10 ml ofwater. The toluene solution is concentrated in a rotary evaporator anddried under a high vacuum. 2.0 g of yellowish oil are obtained. About94% m,p-isomer, about 3% m,m-isomer and about 3% p,p-isomer, determinedby evaluation of the integrals of the aromatic protons, are found in the¹H-NMR spectrum. No water-containing crystals have formed from theliquid m,p-isomer.

A sample of the mother liquor from Example 1d.5 is purified by flashchromatography over silica gel 60 (0.040–0.063 mm) from Merck. A mixtureof ethyl acetate:hexane mixture 1:2 is used as eluant. Verysurprisingly, the largest amount of the meta-para isomer is to be foundin the mother liquor and not in the crystals. About 36% para-para isomerand about 64% meta-para isomer, determined by evaluation of theintegrals of the aromatic protons, are found in the ¹H-NMR spectrum(Example 1d.5a). The proportion of meta-para compound in the crystalshas fallen to about 1–2%. That value is estimated from the differencewith respect to the value in the mother liquor. In the ¹H-NMR spectrumof the crystals, such a low value can only be estimated roughly. Animproved method of determining the distribution of isomers aftercrystallisation is described in Example 1e.

The proportion of meta-para compound in the chromatographed motherliquors is between 60 and 80%, in the case of previous crystallisationof the crude product with water and toluene as solvent. The proportionof meta-para compound in the crystals has in most cases fallen to about1–3%. Those values are calculated from the differences relative to thevalues in the mother liquors. In the ¹H-NMR spectrum of the crystals,such low values can only be estimated roughly.

Comparison Tests EXAMPLE 5 FOR COMPARISON Hydrolysis Analogous toExample 1.3a and Working up Analogous to Method E (Epoxy EtherHydrolysis) as Described in EPA 003 002

Working up Without Addition of Water

139.13 g (1.043 mol) of NaOH concentrated to 30% and 139 ml of deionisedwater and 137.6 g of methanol are combined. The temperature rises toabout 35° C. The mixture is then heated to 50° C. by means of an oilbath. There are then added dropwise in a period of about one hour, withthorough stirring, 319.6 g (0.4348 mol) of a solution, in1,2-dichlorobenzene, of the isomeric mixture ofbis[4-(2-chloro-2-methyl-propionyl)-phenyl]-methane with[3-(2-chloro-2-methyl-propionyl)-phenyl]-[4-(2-chloro-2-methyl-propionyl)-phenyl]-methanefrom the chlorination reaction Example 1.2, additionally diluted with68.7 g of methanol. The internal temperature slowly rises to 55–60° C.The alkaline mixture (about pH 11) is then stirred for about four hoursat 55–60° C. The conversion is checked with a GC sample and a ¹H-NMRsample. The mixture is then cooled to 45° C. and adjusted dropwise to apH of about 1–2 with about 32 g of 16% hydrochloric acid. The colour ofthe emulsion changes from a strong yellow to yellow and the temperaturerises to 53° C. The mixture is then stirred for about 2–3 hours. Theconversion is checked with a ¹H-NMR sample. When the hydrolysis iscomplete, the reaction mixture is neutralised with a small amount ofdilute sodium hydroxide solution (5.5 g). The two phases are separatedat about 50° C. in a separating funnel. 200 ml of water are added to theclear organic phase, which Is then stirred at 60° C. and separated offagain. The phase separation is slow the second time. The cloudy, warmorganic phase is diluted with toluene and then concentrated at 60° C. ina vacuum rotary evaporator in order to remove residual methanol andwater. There are obtained 246.2 g of yellow-reddish solution of the endproduct, an isomeric mixture withbis[4-(2-hydroxy-2-methyl-propionyl)-phenyl]-methane as the mainproduct, dissolved in 1,2-dichlorobenzene.

A small sample does not crystallise out in a test tube, even when seededwith water-free crystals.

A further small sample, which is left to stand in air for two days,slowly crystallises out under the influence of atmospheric moisture. Thecrystals melt at 57.9–59.4° C.

By contrast, a third small sample, to which a drop of water and awater-containing seed crystal are added, crystallises immediately.

The solution of the end product is then concentrated in a vacuum rotaryevaporator at about 60° C. and at about 1 mbar, in order to remove the1,2-dichlorobenzene. 149.7 g of yellow-reddish viscous oil are obtained.This corresponds to a yield of 101.1% of theory (340.42) over all threereaction steps. Two secondary components are still visible in the TLC.The ¹H-NMR spectrum contains, in addition to the isomeric mixture, alsoa small amount of the ketal product. The water content of the crudeproduct is 0.14% by weight in a Karl Fischer water determination. Theoil (Example 5a) still smells a little of 1,2-dichlorobenzene.

A small sample of the concentrated oil does not crystallise out in atest tube, even when seeded with water-free crystals. Even dilution withdiethyl ether does not result in crystallisation.

12.1 g of the concentrated oil are dissolved in 12.0 g of ethyl acetateand introduced onto a chromatography column and separated over about 0.5kg of silica gel (silica gel 60 (0.040–0.063 mm) 230–400 mesh ASTM fromMerck) with a hexane-ethyl acetate mixture (3:1). The fractions arecollected and concentrated in a vacuum rotary evaporator. According toTLC, the product, a thick yellowish oil, is to be found in fractions33–38 (4.2 g) and 39–53 (6.3 g).

The first fraction is pure isomeric mixture (TLC, ¹H-NMR spectrum).

About 87.5% p,p-isomer and about 12.5% m,p-isomer are found in the¹H-NMR spectrum. The second fraction still has a small secondarycomponent in the TLC. According to ¹H-NMR spectrum it is the ketalproduct. The first fraction (Example 5b) begins to crystallise slowlyafter some days, more specifically from the top down. However, it doesnot crystallise through. The water content of the chromatographedproduct is 0.21% by weight in a Karl Fischer water determination. Thesecond fraction remains viscous. Its water content in a Karl Fischerwater determination is 0.30% by weight.

EXAMPLE 6 FOR COMPARISON Preparation of the Epoxy Ether Intermediate andHydrolysis of the Epoxy Ether Intermediate Analogous to Methods D and E(Epoxy Ether Hydrolysis) as Described in EPA 003 002

Working up Without Addition of Water

Preliminary note: The chlorination of the diketone was carried outanalogously to Method A for the halogenation. At the end, the solvent1,2-dichlorobenzene is distilled off in vacuo at 1 mbar. The crudeproduct begins to crystallise out overnight. It is used for the epoxyether synthesis without being purified further.

Method D of EPA 003 002: Preparation of the Epoxy Ether Intermediate:

73.6 g t.q. (0.177 mol t.q.) of the isomeric mixture ofbis[4-(2-chloro-2-methyl-propionyl)-phenyl]-methane with[3-(2-chloro-2-methyl-propionyl)-phenyl]-[4-(2-chloro-2-methyl-propionyl)-phenyl]-methanefrom the chlorination reaction are dissolved in 80 ml of methanolpuriss. and heated. At 45° C. and above, 80.0 g (0.444 mol) of 30%sodium methoxide solution in methanol are then added dropwise. Thetemperature slowly rises to 60° C. and sodium chloride precipitates out.Duration of the dropwise addition is about 30 minutes. The conversion ischecked with a GC. The methanol is then distilled off in a vacuum rotaryevaporator. 100 ml of diethyl ether and 100 ml of water are added to theviscous residue, 98.4 g, and extraction is carried out. The ether phaseis separated off, washed with 10 ml of water and then dried over Na₂SO₄and concentrated. There are obtained 68.75 g t.q. of a viscous brownoil, which is checked with a ¹H-NMR sample. The product, the epoxy etherintermediate, is hydrolysed in the next step according to Method Ewithout being purified further.

Method E of EPA 003 002: Hydrolysis of the Epoxy Ether Intermediate:

200 ml of water are added to 68.75 g t.q. (0.177 mol t.q.) of theisomeric mixture ofbis[4-(2-methoxy-3,3-dimethyl-oxiran-2-yl)-phenyl]-methane with2-methoxy-3,3-dimethyl-2-[4-(3-(2-methoxy-3,3-dimethyl-oxiran-2-yl)-phenyl]methyl-phenyl]-oxiranefrom the epoxy ether stage, and the mixture is heated to 70° C. 1.3 g of16% hydrochloric acid solution are then added dropwise until a pH ofabout 1 is reached. The temperature slowly rises to 83° C. Furtherheating is carried out to reflux at about 87° C. The conversion ischecked with a ¹H-NMR sample. After one hour's reflux, the two-phaseorange reaction mixture is neutralised with 1.7 g of 15% sodiumhydroxide solution and separated in a separating funnel while warm.There are obtained 64.8 g t.q. of a viscous reddish oil, which isdissolved with 150 ml of diethyl ether. The ether solution is dried overNa₂SO₄ and concentrated. 65.4 g t.q. of viscous reddish oil are obtained(Example 6a). This corresponds to a crude yield of 102% of theory. Asecondary component is still visible in the TLC. In the ¹H-NMR spectrum,a small amount of the ketal product is still to be found in addition tothe isomeric mixture. The water content of the crude product is <0.3% ina Karl Fischer water determination.

15.0 g of the crude product are purified by means of flashchromatography over silica gel 60 (0.040–0.063 mm) from Merck. A mixtureof ethyl acetate:hexane mixture 1:3 is used as eluant. 10.9 g of pureproduct are isolated as the main fraction (Example 15b). Thiscorresponds to a yield of 74.1% of theory. It is pure isomeric mixture,a viscous yellowish oil, which does not crystallise. About 87%p,p-isomer and about 13% m,p-isomer are found in the ¹H-NMR spectrum.The water content of the chromatographed product is 0.31% by weight in aKarl Fischer water determination. In the next fraction, 0.4 g of oil,the product still contains a secondary product, which is recognised bymeans of a ¹H-NMR sample as the ketal product.

EXAMPLE 7 FOR COMPARISON Hydrolysis and Working up Analogous to Method F(Epoxy Ether Hydrolysis) as Described in EPA 003 002

Batch: 0.238 mol

Preliminary note: Chlorination of the diketone was carried outanalogously to Method A of EP 003 002. Finally, the solvent1,2-dichlorobenzene is distilled off in vacuo at 1 mbar. The crudeproduct begins to crystallise out overnight. After recrystallisationfrom ethanol, it is used for the hydrolysis according to Method F. M.p.:69.4–71.0° C.

Method F of EPA 003 002: Hydrolysis of the Dichloro Compound:

90.0 g t.q. (0.238 mol) of crystals of the isomeric mixture ofbis[4-(2-chloro-2-methyl-propionyl)-phenyl]-methane with[3-(2-chloro-2-methyl-propionyl)-phenyl]-[4-(2-chloro-2-methyl-propionyl)-phenyl]-methanefrom the chlorination reaction are heated at reflux with 229.1 g (0.572mol) of 10% sodium hydroxide solution. At about 70° C., the dichlorocompound melts and, when stirred, yields an emulsion. At 94° C., gentlereflux begins. After 25 minutes, about 3.9% starting material have beenconverted, after 2 hours about 7.6% and after 4 hours about 14% startingmaterial (estimate from the ¹H-NMR spectrum). Only starting material,mono compound and product are to be found in the thin-layerchromatogram. In order to accelerate the hydrolysis, the mixture iscooled to 60° C. and then 100 g of methanol are added as solvent and themixture is heated to reflux (about 60° C.). After 30 minutes, about 80%starting material (estimate from the ¹H-NMR spectrum) have beenconverted, and after 90 minutes all the starting material has beenconverted. The emulsion is diluted at 62° C. with 100 g of toluene andcooled to 43° C. When 21.8 g of 16% hydrochloric acid solution are addedin order to achieve a pH of 1–2, the temperature rises to 49° C. Theemulsion is heated to reflux again (about 60° C.) and then stirred for 2hours until all the ketal (monitoring with the ¹H-NMR spectrum) has beenhydrolysed. The emulsion is then adjusted to pH 7 with 1.2 g of 15%sodium hydroxide solution. The aqueous phase is separated off in aseparating funnel and extracted with 20 g of toluene. The organic phaseis washed with 20 g of water and then combined with the toluene used forwashing. The organic phase is then concentrated in a vacuum rotaryevaporator. 82.3 g of yellow oil are obtained. This is dissolved againin 200 g of toluene and then dried over Na₂SO₄ and concentrated in avacuum rotary evaporator. There are obtained 81.3 g of viscous yellowoil, which does not crystallise. This corresponds to a t.q. yield of100.3% of theory (340.42). It is an isomeric mixture (Example 7a) withbis[4-(2-hydroxy-2-methyl-propionyl)-phenyl]-methane as the maincomponent. The structure is confirmed with a ¹H-NMR sample. Thecomposition in the isomeric mixture has shifted markedly in favour ofthe p,p-isomer. This was caused by the recrystallisation of the dichlorocompound. The water content of the crude product is 0.30% by weight in aKarl Fischer water determination. After standing for a relatively longperiod of time, the crude product solidifies. The crystals melt at87.1–89.0° C.

19.09 of the crude product are purified by means of flash chromatographyover silica gel 60 (0.040–0.063 mm) from Merck. A mixture of ethylacetate:hexane mixture 1:3 is used as eluant. 10.5 g of pure product(Example 7b) are isolated as the main fraction. This corresponds to ayield of 55.4% of theory. It is a viscous yellowish oil which initiallydoes not crystallise. In the ¹H-NMR spectrum, only traces of them,p-isomer are found in addition to the p,p-isomer. The water content ofthe chromatographed product is 0.50% by weight in a Karl Fischer waterdetermination. In the next fraction, 7.0 g of oil, the product stillcontains a small amount of a secondary product, which is recognised as aketal product by means of a ¹H-NMR sample.

After standing for a relatively long period of time, the oilcrystallises. The crystals melt at 89.6–91.6° C. FIG. 5 shows the X-raypowder spectrum with the characteristic lines at a 2-theta angle of10.77; 11.27; 16.49; 17.27; 17.89; 21.57; 22.63; 26.05; 28.75.

EXAMPLE 8 Example for Determining the Hygroscopicity

It was observed on various occasions in the case of the water-freeproducts that they are hygroscopic at room temperature and crystallise,or change crystal form, under the effect of moist air. In order to checkthis, samples of water-free products, products containing isomers aswell as isomerically pure products, are placed into small Petri dishes,in the form of an oil or in the form of a solidified mass, and thenspread flat. The Petri dishes are stored at room temperature in adesiccator, which contains a dish of water.

Samples from the following Examples are weighed out:

-   Example 1.3c-   Example 2-   Example 3.3c-   Example 5a-   Example 6a-   Example 7a

As the days pass, the habit of the samples changes and they allcrystallise. After two weeks, samples are removed and the water contentis determined according to Karl Fischer. In all samples, it is nowbetween 3.9 and 4.8% with a theoretical content of 5.03% for one waterof crystallisation per molecule. After one month, the resulting crystalsare pulverised in an agate mortar and submitted for the recording of anX-ray powder spectrum. At the same time, the water content is determinedaccording to Karl Fischer. In all samples it is now between 4.6 and 5.1%with a theoretical content of 5.03% for one water of crystallisation permolecule. All the X-ray powder spectra of the samples are now typical ofwater-containing crystals. FIGS. 6 to 11 show the X-ray powder spectraof the samples with the characteristic lines at a 2-theta angle of 6.70;9.70; 14.00; 14.90; 15.19; 15.59; 15.99; 16.43; 17.67; 19.85; 20.27;21.45; 22.25; 26.00; 28.83.

For comparison, three further samples are submitted for the recording ofan X-ray powder spectrum. (FIGS. 12 to 14) A common feature of all thesesamples is that they have a markedly lower water content, from 2.0 to3.9%, than the usual water-containing samples. They are produced by thesubsequent forced removal of water of crystallisation, for example bydistillation or after-drying of water-containing crystals under a highvacuum. A common feature of all three samples is that they nowsimultaneously have the characteristic lines for water-containing andwater-free crystals. These are the samples Example 1.3c, Example 1.3aand Example 3.3c after-dried under HV. The forced after-drying in avacuum rotary evaporator has the particularly unexpected effect that thecrystals cake together to form non-dusty loose spherules which arereadily pourable.

Using the product bis[4-(2-methyl-propionyl)-phenyl]-methane and theisomeric mixture, it is also possible to prepare crystals with methanolinstead of with water. Unfortunately, the methanol slowly evaporates ondrying or when left to stand in the air. The crystals are too unstable.

Notes Relating to the Examples

The water-containing crystals from the various Examples are unstableabove 50° C. and begin slowly to lose water. Because of this phenomenon,the melting point determinations are subject to systematic error andbecome inaccurate. Depending on the rate of heating, differing resultsare obtained. Furthermore, the water-containing crystals can becomereorganised during storage and have a higher melting range after someweeks.

On drying of the water-containing crystals under a very good vacuum, aportion of the water of crystallisation is lost. If drying is carriedout at higher temperatures, the water-containing crystals can begin tosinter.

The water-free crystals tend to be amorphous and crystallise withdifficulty. However, they melt at a markedly higher temperature. Theyare highly soluble in organic solvents. The water-containing crystalsare less readily soluble in organic solvents and can therefore beisolated more readily from crude products.

The water-free crystals are markedly hygroscopic at room temperature.When they are stored in a desiccator over a dish of water, they absorbmost of the possible water within days or weeks. In so doing, thecrystals change in appearance and become powdery.

The X-ray powder spectra of water-containing and water-free crystalsdiffer greatly. However, the differences in the X-ray powder spectrabetween the isomerically pure crystals and the isomeric mixtures fromthe Examples are slight. The crystals crystallise with the same unitcell in each case.

APPLICATION EXAMPLES Example A1 Overprint Coating Formulation (withAminoacrylate)

Component % by wt. Ebecryl 605 30.0 Ebecryl 7100 10.0 Ebecryl 40 5.0 OTA480 30.0 TPGDA 24.0 Ebecryl 1360 0.5 Dow Corning 57 0.5 Σ 100.0 OTA 480:a glycerol propoxylate triacrylate (UCB) TPGDA: tripropylene glycoldiacrylate Ebecryl 605: bisphenol A epoxy acrylate, diluted with 25%TPGDA (UCB) Ebecryl 7100: aminoacrylate (UCB) Ebecryl 40:pentaerythritol ethoxylate tetraacrylate (UCB) Ebecryl 1360 siliconeacrylate Dow Corning 57: silicone additive, flow improver

In each case 0.6 g of photoinitiator was weighed in per 10 g offormulation.

-   UV exposure device (IST): Two 120 W/cm medium-pressure mercury    lamps, variable-speed conveyor belt-   Curing rate: Determination of the stability against wiping of the    cured clear coats; figure given in terms of m/min conveyor belt    speed of the UV exposure device; applied layer thickness 6 μm    (Erichson knife device) on cardboard-   Yellowing/gloss: Measurement of the b* value 15 min after curing    (curing at a conveyor belt speed of the UV exposure device of 10    m/min); applied layer thickness 100 μm (manual knife) on    white-coated chipboard. The measuring angle for the gloss    measurement is 20°.-   Odour rating: Curing of the clear coats at a predetermined curing    rate, applied layer thickness 6 μm on aluminium foil. Rating:    0=odourless, 1=very slight, 2=slight, 3=marked, 4=pronounced, 5=very    pronounced. Inherent odour of the substrate: 1.

The following Tables show the results:

a) Comparison Between Water-Containing Product Para-Para Compound) andDarocur 1173, Irgacure 184, Irgacure 500, Irgacure 2959, Esacure KIP 150and Esacure KIP 100 F

Curing Photoinitiator rate Gloss Odour Example [m/min] b* [%] rating3.3a 190 8.5 91 3 Darocur 1173 70 7.8 87 5 Irgacure 184 60 7.3 89 5Irgacure 2959 60 7.8 89 3 Esacure KIP 150 90 7.1 88 3 Esacure KIP 100 F80 7.6 89 3 Darocur 1173: 2-hydroxy-2-methyl-1-phenylpropan-1-one (Ciba)Irgacure 184: (1-hydroxy-cyclohexyl)phenyl ketone (Ciba) Irgacure 2959:1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (Ciba)Esacure KIP 150:oligo-[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone],(Lamberti) Esacure KIP 100F:oligo-[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)-phenyl]-propanone +2-hydroxy-2-methyl-1-phenylpropan-1-oneb) Comparison Between Water-Containing Product and Water-Free ProductAccording to EP 003 002

Photoinitiator Curing rate Odour Example [m/min] b* Gloss [%] rating1.3a 180 9.0 88 2.5 2 180 9.2 88 2.5 5a 160 10.9 88 3 5b 170 9.5 88 2 7a180 8.9 88 2.5 7b 180 9.1 88 2.5c) Comparison Between Water-Containing Low-Melting Product andWater-Containing High-Melting Product

Photoinitiator Curing rate Odour Example [m/min] b* Gloss [%] rating1.3a 170 9.3 88 2.5 68–70° C. 1.3b 180 9.5 88 2.5 71–74° C. 1.3c 180 8.888 2.5 87–90° C.d) Comparison Between Water-Containing Product of Isomeric Mixture,Water-Containing Product of Pure Para-Para Compound and Water-FreeProduct of Pure Meta-Para Compound

Photoinitiator Curing rate Odour Example [m/min] b* Gloss [%] rating1.3a 180 9.0 88 2.5 3.3c 190 9.2 88 2.5 4.3 150 7.8 85 2.5e) Comparison Between Water-Free Product of Isomeric Mixture andWater-Free Product of Pure Para-Para Compound

Photoinitiator Curing rate Odour Example [m/min] b* Gloss [%] rating 2180 9.2 88 2.5 3.3b 180 9.3 88 2.5 5b 170 9.5 88 2f) Comparison Between Water-Containing Product of Isomeric Mixture withKnown Meta-Para Content, Water-Free Product of Isomeric Mixture from theChromatographed Mother Liquor, and Water-Free Product of Pure Meta-ParaCompound

Photoinitiator Curing rate Odour Example [m/min] b* Gloss [%] rating 1.e180 6.8 88 2  1% m-p 1.f 180 8.5 88 2  12% m-p 1.fa 180 7.5 87 2  4% m-p1.fb 170 7.0 86 2.5  7% m-p 1d.5a 170 9.0 85 2.5  64% m-p 4.3 150 7.8 852.5 100% m-p

Example A2 Overprint Coating Formulation (Without Aminoacrylate)

Component % by wt. Ebecryl 605 35.0 Ebecryl 40 10.0 OTA 480 30.0 TPGDA24.0 Ebecryl 1360 0.5 Dow Corning 57 0.5 Σ 100.0 OTA 480: a glycerolpropoxylate triacrylate (UCB) TPGDA: tripropylene glycol diacrylateEbecryl 605: bisphenol A epoxy acrylate, diluted with 25% TPGDA (UCB)Ebecryl 40: pentaerythritol ethoxylate tetraacrylate (UCB) Ebecryl 1360silicone acrylate Dow Corning 57: silicone additive, flow improver

In each case 0.6 g (or 0.8 g) of photoinitiator was weighed in per 10 gof formulation.

-   UV exposure device (IST): Two 120 W/cm medium-pressure mercury    lamps, variable-speed conveyor belt-   Curing rate: Determination of the stability against wiping of the    cured clear coats; figure given in terms of m/min conveyor belt    speed of the UV exposure device; applied layer thickness 6 μm    (Erichson knife device) on cardboard-   Yellowing/gloss: Measurement of the b* value 15 min after curing    (curing at a conveyor belt speed of the UV exposure device of 10    m/min); applied layer thickness 100 μm (manual knife) on    white-coated chipboard. The measuring angle for the gloss    measurement is 20°.-   Odour rating: Curing of the clear coats at a predetermined curing    rate, applied layer thickness 6 μm on aluminium foil. Rating:    0=odourless, 1=very slight, 2=slight, 3=marked, 4=pronounced, 5=very    pronounced. Inherent odour of the substrate: 1.

The following Tables show the results:

a) Comparison Between Water-Containing Product (Pure Para-Para Compound)and Darocur 1173, Irgacure 184, Irgacure 500, Irgacure 2959, Esacure KIP150 and Esacure KIP 100 F with 0.6 g of Photoinitiator

Photoinitiator Curing rate Gloss Odour Example [m/min] b* [%] rating3.3a 100 11.8 89 3 Darocur 1173 30 7.2 86 4 Irgacure 184 20 6.1 88 4Irgacure 2959 40 6.3 88 2 Esacure KIP 150 60 8.3 89 3 Esacure KIP 100 F40 7.0 89 3 Darocur 1173: 2-hydroxy-2-methyl-1-phenylpropan-1-one (Ciba)Irgacure 184: (1-hydroxy-cyclohexyl)phenyl ketone (Ciba) Irgacure 2959:1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propan-1-one (Ciba)Esacure KIP 150:oligo-[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propanone],(Lamberti) Esacure KIP 100 F:oligo-[2-hydroxy-2-methyl-1-[4-(1-methylvinyl)-phenyl]-propanone +2-hydroxy-2-methyl-1-phenylpropan-1-oneb) Comparison Between Water-Containing Product (Pure Para-Para Compound)and Darocur 1173, Irgacure 184, Irgacure 500, Irgacure 2959, Esacure KIP150 and Esacure KIP 100 F with 0.8 g of photoinitiator

Photoinitiator Curing rate Gloss Odour Example [m/min] b* [%] rating3.3a 200 10.8 91 3 Darocur 1173 60 6.9 88 5 Irgacure 184 60 6.7 89 5Irgacure 2959 60 6.5 88 2 Esacure KIP 150 120 8.6 89 3 Esacure KIP 100 F80 7.6 89 3c) Comparison Between Water-Containing Product and Water-Free ProductAccording to EP 003 002

Curing Photoinitiator rate Odour Example [m/min] b* Gloss [%] rating1.3a 100 11.3 89 2.5 2 90 12.2 86 3 5a 70 13.2 87 3.5 5b 100 12.2 87 2.57a 100 12.0 88 2.5 7b 100 11.8 88 2.5d) Comparison Between Water-Containing Low-Melting Product andWater-Containing High-Melting Product with 0.6 g of Photoinitiator

Photoinitiator Curing rate Odour Example [m/min] b* Gloss [%] rating1.3a 100 12.0 88 2.5 68–70° C. 1.3b 90 11.8 88 2.5 71–74° C. 1.3c 10012.0 89 2.5 87–90° C.e) Comparison Between Water-Containing Product of Isomeric Mixture,Water-Containing Product of Pure Para-Para Compound and Water-FreeProduct of Pure Meta-Para Compound with 0.6 g of Photoinitiator

Photoinitiator Curing rate Odour Example [m/min] b* Gloss [%] rating1.3a 100 12.0 88 2.5 3.3c 100 11.8 87 3 4.3 60 8.0 85 2f) Comparison Between Water-Free Product of Isomeric Mixture andWater-Free Product of Pure Para-Para Compound with 0.6 g ofPhotoinitiator

Photoinitiator Curing rate Odour Example [m/min] b* Gloss [%] rating 290 12.2 86 3 3.3b 100 12.0 88 3 5b 100 12.2 87 2.5g) Comparison Between Water-Containing Product of Isomeric Mixture withKnown Meta-Para Content, Water-Free Product of Isomeric Mixture from theChromatographed Mother Liquor, and Water-Free Product of Pure Meta-ParaCompound

Photoinitiator Curing rate Odour Example [m/min] b* Gloss [%] rating 1.e100 12.0 88 2  1% m-p 1.f 100 13.0 88 2  12% m-p 1.fa 90 12.8 87 2.5  4%m-p 1.fb 90 12.8 86 2.5  7% m-p 1d.5a 60 10.0 84 2.5  64% m-p 4.3 60 8.085 2 100% m-p

Example A3 Powder Coating Formulation

Component % by weight Uracross P3125 (unsaturated polyester resin fromDSM) 76.5 Uracross P3307 (vinyl ether polyurethane resin from DSM) 20Worlee add 902 (flow agent from Worlée Chemie) 0.5 Resiflow PV5 (flowagent from Worlée Chemie) 1.0 Photoinitiator 2.0 Σ 100.0

Extruded at 70° C. (Prism TS 16 Twin Screw Extruder)

The clear powder coating is applied to white-coated chipboard and toglass. (Wagner turbo gun); layer thickness: 75+/−5 μm. The coatedsamples are melted under an IR lamp (2 min, 140° C.) and cured.

UV exposure device (IST):Hg- and Fe-doped lamps each of 240 W/cm,Variable-speed conveyor belt, (curing rate: 10, 20 or 40 m/min)

Test Method:

König pendulum hardness according to DIN 53157.

Measurement was carried out directly after curing (0 h) and after 24 h.

Methyl ethyl ketone blister test: The time until the coating begins tocome away is measured.

Methyl ethyl ketone soak test, the loss in weight in % is measured.

Pendulum MEK MEK Curing hardness blister soak test b* Photo- rate (sec)test (min) % value initiator m/min 0 h 24 h 0 h 24 h 0 h 0 h Irgacure 10132 146 33 35 1.4 1.1 184 20 125 137 28 28 0.2 40 115 126 14 14 −0.7Example 10 112 119 20 19 1.3 3.6 1.3a 20 109 132 14 16 −3.7 1.7 40 97116 15 09 −2.7 0.7

Example A4 Formulation for Blue Flexographic Printing Ink

IRR 440 (acrylic oligomer in acrylate)s 26.9 OTA 480 19.0 Ebecryl 645(modified bisphenol A epoxy acrylate) 18.0 Hexanediol diacrylate 13.0Ebecryl 220 (hexafunctional aromatic urethane acrylate (UCB)) 10.0Ebecryl 168 (acidic methacrylate, adhesion agent) 1.3 Dow Corning 57²0.7 Irgalite Blue GLO³ 11.1 Σ 100.0

-   UV exposure device (IST): One 120 W/cm medium-pressure mercury lamp,    variable-speed conveyor belt-   Substrate: white PE film-   Application: test assembly, 1.38 g/m², corresponds to an optical    density of 1.45-   Properties tested: through-curing (TC), surface curing (SF)    Results of the Comparison Tests

Concentration TC SF Product [% by wt.] [m/min] [m/min] Example 1.3a 6120 110 Example 1.3a 8 160 140 IRGACURE 369¹ 6 90 170 IRGACURE 369¹ 8150 200 IRGACURE 907¹ + 6 + 0.5 100 100 QUANTACURE ITX² IRGACURE 1300¹ 620 20 IRGACURE 1300¹ 8 70 100 Irgacure 369:2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 IRGACURE1300¹ (30% Irgacure 369 + 70% Irgacure 651) Irgacure 651:2,2-dimethoxy-1,2-diphenylethan-1-one ¹Ciba Specialty Chemicals ²Lambson

Example A5 Example of a Dispersion in Water

Preparation of an Aqueous Photoinitiator Formulation

-   40% photoinitiator of Example 1.3a-   4% dispersant, sodium salt of a carboxylic acid copolymer,    ^(RTM)OROTAN 731 DP from Rohm+Haas Company;-   0.1% bactericide, 1,2-benzisothiazol-3-one, ^(RTM)PROXEL BD from    Novartis AG;-   55.9% water (deionised).    1.1 Preparation of the Suspension

In a glass beaker,

0.6 g of bactericide (^(RTM)PROXEL BD) and 26.0 g of dispersant(^(RTM)OROTAN DP 731) are dissolved in 363.4 g of deionised water atroom temperature. 260.0 g of photoinitiator are introduced into theresulting solution, and stirring is carried out for about one hour. 650g of an aqueous suspension are obtained.1.2 Pre-grinding

At room temperature, the suspension obtained according to Example A51.1is pre-ground three times in a cross-toothed colloid mill (stator-rotorprinciple, water-cooled; from Fryma AG Maschinenbau, Rheinfelden,Switzerland) by a repeating process with the narrowest grinding gapsetting. The temperature of the suspension does not exceed 35° C. duringthe grinding. After the grinding operation, the largest particles have adiameter of about 100 micrometers.

1.3 Fine Grinding

An impeller-type ball mill (Bachofen KDL type with 0.6 litre grindingcylinder) Is filled with 80–83% by volume of glass beads having adiameter of 1 mm (=480–500 g of glass beads, based on the capacity ofthe grinding cylinder), and the water cooling of the mill is set inoperation. At room temperature, the aqueous suspension pre-groundaccording to Example 1.2 is finely ground three times by a repeatingprocess at a shaft speed of 2000 rev/min by means of the impeller-typeball mill. The throughput Is about 9 litres of suspension/hour. Thetemperature of the grinding stock is kept below 35° C. by jacketcooling. After the third grinding pass, the necessary fineness ofparticle size has been achieved. The particle size distribution in thesuspension is determined using a laser granulometer. The 50% medianvalue is about 2.5 micrometers; the largest particles have a diameter ofabout 12 micrometers. A homogeneous formulation that flows readily atroom temperature is obtained; its storage stability at 20–25° C. is morethan one month (i.e. no sedimentation and no phase separation occur).

Example A6

A clear Dual-Cure-System based on polyurethenes is prepared by mixing:

21.1 Parts Desmophen ® LS 2009/1, hydroxy functional polyacrylate,(Bayer AG) 32.3 Parts Roskydal ® FWO 2518C, isocyanurate based urethaneacrylate, 80% in butyl acetate (Bayer AG) Parts Baysilone ® OL 17, flowimprover, 10% in Xylene (Bayer AG) 0.3 Parts Modaflow ®, flow improver(Monsanto) 0.3 Parts 1-Methoxy-2-propanol, (Fluka Chemicals) 26.0 PartsByk ® 306, flow improver (Byk-Chemie) 0.5 Parts Roskydal ® FWO 2545 E,urethane acrylate with isocyanate groups 11.2 (Bayer AG)

The samples were prepared by adding 3% of photoinitator as given in thetable below.

The mixtures were applied to a white coil-coat aluminum, air-dried for 5minutes at room temperature an heated on a hot plate at 120° C. for 10minutes. Irradiation is the carried out using a Panacol F-450 Lamp withUVA emission. A tack free dry film with a thickness of approximately 40μm is obtained.

45 Minutes after cure, the pendulum hardness according to König (DIN53157) is measured.

pendulum hardness Initiator [sec]   3% (Example 1.3a + Irgacure 819 819(5:1)) 95 1.5% Tinuvin 400 + 1% Tinuvin 292 Irgacure 819 (Ciba)(Bis(2,4,6-trimethylbenzoyl)-phenylphosphineoxide) Tinuvin 400 (Ciba) (amixture of2-[4-[(2-Hydroxy-3-dodecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazineand2-[4-[(2-Hydroxy-3-tridecyloxypropyl)oxy]-2-hydroxyphenyl]-4,6-bis(2,4-dimethylphenyl)-1,3,5-triazine)Tinuvin 292(Ciba) ((1,2,2,6,6-pentamethyl-4-piperidinyl)sebacate)

Example A7 Curing of a UV-Curable Clear Lacquer as Wsed, for Example inthe Automotive Industry.

A UV-curable clear lacquer is prepared by mixing the followingcomponents:

80.0 parts of a hexafunktional urethane acrylate (Ebecryl 1290) 20.0parts Butylacetate (Solvent)

3% of the photoinitiator combination based on solids were welldissolved.

The Combination are 5 Parts from Example 1.3a combined with 1 partIrgacure 819. In addition 1.5% Tinuvin 400 And 1% Tinuvin 292 are added.The mixture is applied to a white cil coat aluminum panel and is curedusing a Panacol F450 Lamp. The exposure time was 5 Min. A non-stickycured film approximately 50 μm thick is obtained. 30 minutes aftercuring, the pendulum hardness according to König (DIN 53157) isdetermined in seconds. The higher the value, the greater is the hardnessof the crosslinked surface.

The pendulum hardness measured is 147 s.

SUMMARY EXPLANATION OF THE FIGURES

FIGS. 1 and 2 show the X-ray powder spectra of water-containing isomericmixtures of the compounds of formulae Ia and IIa.

FIG. 3 shows the X-ray powder spectrum of the water-free isomericmixture of the compounds of formulae I and II.

FIG. 4 shows the X-ray powder spectrum of the water-containing purepara-para compound of formula IIa.

FIG. 5 shows the X-ray powder spectrum of the water-free pure para-paracompound of formula II.

FIGS. 6 to 11 show the X-ray powder spectra of water-containingcompounds, the water absorption having taken place owing to thehygroscopic properties of the water-free compounds, (Example 8)

FIGS. 6 to 7, 9 to 11 show the X-ray powder spectra of water-containingisomeric mixtures of the compounds of formulae Ia and IIa.

FIG. 8 shows the X-ray powder spectrum of the water-containing purepara-para compound of formula IIa.

FIGS. 12 to 14 show the X-ray powder spectra of water-containingisomeric mixtures of the compounds of formulae Ia and IIa with a smallerwater content after removal of a portion of the water of crystallisation(Example 8).

1. A crystalline isomeric mixture of α-hydroxy ketone compounds offormulae Ia and IIa

where the water content is from 2 to 8% by weight.
 2. An isomericmixture according to claim 1, having a content of para-para compound offrom 99.9 to 25% by weight and having a content of meta-para compound offrom 0.1 to 75% by weight.
 3. A process for the preparation of acrystalline isomeric mixture of compounds of formulae Ia and IIaaccording to claim 1, which process comprises reacting diphenylmethanewith isobutyric acid halide in the presence of a Friedel-Craftscatalyst, and chlorinating and hydrolysing the resulting isomericmixture consisting of bis[4-(2-methyl-propionyl)-phenyl]-methane and[3-(2-methyl-propionyl)-phenyl]-[4-(2-methyl-propionyl)-phenyl]methane,hydrolysis of the isomeric mixture yielding an aqueous phase and anorganic phase that comprises the hydrolysis product; wherein furtherprocessing of the hydrolysis product comprises the following steps a)addition of from 3 to 20% by weight of water to the organic phase,crystallisation and isolation of the water containing isomeric mixtureof formulae Ia and IIa and b) where appropriate, drying of the isomericmixture obtained in step a) to remove excess water and obtain acrystalline isomeric mixture.
 4. A composition comprising (A) at leastone ethylenically unsaturated compound, (B) an isomeric mixture ofcompounds of formulae Ia and IIa according to claim 1, (C) optionally afilm-forming binder based on a thermoplastic or thermocurable resin; (D)optionally, further additives, (E) optionally, further photoinitiatorsand coinitiators.
 5. A process for the production of a scratch-resistantdurable surface, wherein (1) a composition according to claim 4 isprepared; (2) the formulation is applied to a support; and (3) curing ofthe formulation is carried out either only by means of irradiation withelectromagnetic radiation having a wavelength of from 200 nm to withinthe IR range, or by irradiation with electromagnetic radiation andprior, simultaneous and/or subsequent action of heat.
 6. A processaccording to claim 5 for the production of pigmented and non-pigmentedsurface coatings, overprint coatings, powder coatings, printing inks,gel coats, composite materials or glass fibre coatings.
 7. A coatedsubstrate which is coated on at least one surface with a curedcomposition according to claim
 4. 8. A composition comprising (A) anethylenically unsaturated compound containing at least oneaminoacrylate, (B) an isomeric mixture of compounds of formulae Ia andIIa according to claim 1, (C) optionally a film-forming binder based ona thermoplastic or thermocurable resin; (D) optionally, furtheradditives, (E) optionally, further photoinitiators and coinitiators. 9.A process for the production of a scratch-resistant durable surface,wherein (1) a composition according to claim 8 is prepared; (2) theformulation is applied to a support; and (3) curing of the formulationis carried out either only by means of irradiation with electromagneticradiation having a wavelength of from 200 nm to within the IR range, orby irradiation with electromagnetic radiation and prior, simultaneousand/or subsequent action of heat.
 10. A process according to claim 9 forthe production of pigmented and non-pigmented surface coatings,overprint coatings, powder coatings, printing inks, gel coats, compositematerials or glass fibre coatings.
 11. A coated substrate which iscoated on at least one surface with a cured composition according toclaim 8.